LSAT Prep Test 85 - Reading Comprehension - Answers (No Explanations)

The United States Supreme Court’s 1948 ruling in Shelley v. Kraemer famously disallowed state courts from enforcing racially restrictive covenants. Such covenants are, in essence, private legal obligations (5) included in the deed to a property requiring that only members of a certain race be allowed to occupy the property. Because it prohibited the enforcement of these covenants, the Court’s decision in Shelley v. Kraemer is justly celebrated for overturning a key (10) instrument of housing discrimination. However, while few would deny that racially restrictive covenants are unjust, the stated legal rationale for the Shelley decision has nevertheless proven to be problematic.

The Shelley Court relied on the Fourteenth (15) Amendment to the U.S. Constitution, which grants equal protection under the law to all U.S. citizens. This amendment had long been held to apply to state actors but not individuals. Shelley did not purport to alter this. But where, then, was the state action that is (20) necessary for invoking the Fourteenth Amendment, given that the restrictive covenants were private contracts? The Court’s answer was that although the restrictive covenants themselves were perfectly legal, judicial enforcement of the covenants violated the (25) Fourteenth Amendment because responsibility for a contract’s substantive provisions should be attributed to the state when a court enforces it. According to this “attribution” rationale, courts could enforce only those contractual provisions that could have been enacted (30) into general law. Because the Fourteenth Amendment would not have allowed a law that banned members of a certain race from purchasing property, it followed from Shelley’s analysis that judicial enforcement of racially restrictive covenants also was unconstitutional.

(35) Shelley’s attribution logic threatened to dissolve the distinction between state action, to which Fourteenth Amendment limitations apply, and private action, which falls outside of the Fourteenth Amendment’s purview. After all, Shelley’s approach, (40) consistently applied, would require individuals to conform their private agreements to constitutional standards whenever, as is almost always the case, the individuals want the option of later seeking judicial enforcement. Primarily for this reason, neither the (45) Supreme Court nor lower courts later applied Shelley’s approach. Courts routinely enforce contracts whose substantive provisions could not have been constitutionally enacted by government. For instance, courts regularly enforce settlement agreements that (50) limit the settling party’s ability to speak publicly in various respects, despite the fact that statutory limitations on the identical speech would represent an unconstitutional violation of free speech.

Additionally, there is a particularly noxious aspect (55) of the Shelley Court’s analytics—namely, the Court’s conclusion that racially restrictive covenants themselves were perfectly legal. The legal rationale behind the Shelley decision thus failed to target the genuine problem with racially restrictive covenants: (60) what was troubling was not the covenants’ enforcement but their substantive content.

The United States Supreme Court’s 1948 ruling in Shelley v. Kraemer famously disallowed state courts from enforcing racially restrictive covenants. Such covenants are, in essence, private legal obligations (5) included in the deed to a property requiring that only members of a certain race be allowed to occupy the property. Because it prohibited the enforcement of these covenants, the Court’s decision in Shelley v. Kraemer is justly celebrated for overturning a key (10) instrument of housing discrimination. However, while few would deny that racially restrictive covenants are unjust, the stated legal rationale for the Shelley decision has nevertheless proven to be problematic.

The Shelley Court relied on the Fourteenth (15) Amendment to the U.S. Constitution, which grants equal protection under the law to all U.S. citizens. This amendment had long been held to apply to state actors but not individuals. Shelley did not purport to alter this. But where, then, was the state action that is (20) necessary for invoking the Fourteenth Amendment, given that the restrictive covenants were private contracts? The Court’s answer was that although the restrictive covenants themselves were perfectly legal, judicial enforcement of the covenants violated the (25) Fourteenth Amendment because responsibility for a contract’s substantive provisions should be attributed to the state when a court enforces it. According to this “attribution” rationale, courts could enforce only those contractual provisions that could have been enacted (30) into general law. Because the Fourteenth Amendment would not have allowed a law that banned members of a certain race from purchasing property, it followed from Shelley’s analysis that judicial enforcement of racially restrictive covenants also was unconstitutional.

(35) Shelley’s attribution logic threatened to dissolve the distinction between state action, to which Fourteenth Amendment limitations apply, and private action, which falls outside of the Fourteenth Amendment’s purview. After all, Shelley’s approach, (40) consistently applied, would require individuals to conform their private agreements to constitutional standards whenever, as is almost always the case, the individuals want the option of later seeking judicial enforcement. Primarily for this reason, neither the (45) Supreme Court nor lower courts later applied Shelley’s approach. Courts routinely enforce contracts whose substantive provisions could not have been constitutionally enacted by government. For instance, courts regularly enforce settlement agreements that (50) limit the settling party’s ability to speak publicly in various respects, despite the fact that statutory limitations on the identical speech would represent an unconstitutional violation of free speech.

Additionally, there is a particularly noxious aspect (55) of the Shelley Court’s analytics—namely, the Court’s conclusion that racially restrictive covenants themselves were perfectly legal. The legal rationale behind the Shelley decision thus failed to target the genuine problem with racially restrictive covenants: (60) what was troubling was not the covenants’ enforcement but their substantive content.

The United States Supreme Court’s 1948 ruling in Shelley v. Kraemer famously disallowed state courts from enforcing racially restrictive covenants. Such covenants are, in essence, private legal obligations (5) included in the deed to a property requiring that only members of a certain race be allowed to occupy the property. Because it prohibited the enforcement of these covenants, the Court’s decision in Shelley v. Kraemer is justly celebrated for overturning a key (10) instrument of housing discrimination. However, while few would deny that racially restrictive covenants are unjust, the stated legal rationale for the Shelley decision has nevertheless proven to be problematic.

The Shelley Court relied on the Fourteenth (15) Amendment to the U.S. Constitution, which grants equal protection under the law to all U.S. citizens. This amendment had long been held to apply to state actors but not individuals. Shelley did not purport to alter this. But where, then, was the state action that is (20) necessary for invoking the Fourteenth Amendment, given that the restrictive covenants were private contracts? The Court’s answer was that although the restrictive covenants themselves were perfectly legal, judicial enforcement of the covenants violated the (25) Fourteenth Amendment because responsibility for a contract’s substantive provisions should be attributed to the state when a court enforces it. According to this “attribution” rationale, courts could enforce only those contractual provisions that could have been enacted (30) into general law. Because the Fourteenth Amendment would not have allowed a law that banned members of a certain race from purchasing property, it followed from Shelley’s analysis that judicial enforcement of racially restrictive covenants also was unconstitutional.

(35) Shelley’s attribution logic threatened to dissolve the distinction between state action, to which Fourteenth Amendment limitations apply, and private action, which falls outside of the Fourteenth Amendment’s purview. After all, Shelley’s approach, (40) consistently applied, would require individuals to conform their private agreements to constitutional standards whenever, as is almost always the case, the individuals want the option of later seeking judicial enforcement. Primarily for this reason, neither the (45) Supreme Court nor lower courts later applied Shelley’s approach. Courts routinely enforce contracts whose substantive provisions could not have been constitutionally enacted by government. For instance, courts regularly enforce settlement agreements that (50) limit the settling party’s ability to speak publicly in various respects, despite the fact that statutory limitations on the identical speech would represent an unconstitutional violation of free speech.

Additionally, there is a particularly noxious aspect (55) of the Shelley Court’s analytics—namely, the Court’s conclusion that racially restrictive covenants themselves were perfectly legal. The legal rationale behind the Shelley decision thus failed to target the genuine problem with racially restrictive covenants: (60) what was troubling was not the covenants’ enforcement but their substantive content.

The United States Supreme Court’s 1948 ruling in Shelley v. Kraemer famously disallowed state courts from enforcing racially restrictive covenants. Such covenants are, in essence, private legal obligations (5) included in the deed to a property requiring that only members of a certain race be allowed to occupy the property. Because it prohibited the enforcement of these covenants, the Court’s decision in Shelley v. Kraemer is justly celebrated for overturning a key (10) instrument of housing discrimination. However, while few would deny that racially restrictive covenants are unjust, the stated legal rationale for the Shelley decision has nevertheless proven to be problematic.

The Shelley Court relied on the Fourteenth (15) Amendment to the U.S. Constitution, which grants equal protection under the law to all U.S. citizens. This amendment had long been held to apply to state actors but not individuals. Shelley did not purport to alter this. But where, then, was the state action that is (20) necessary for invoking the Fourteenth Amendment, given that the restrictive covenants were private contracts? The Court’s answer was that although the restrictive covenants themselves were perfectly legal, judicial enforcement of the covenants violated the (25) Fourteenth Amendment because responsibility for a contract’s substantive provisions should be attributed to the state when a court enforces it. According to this “attribution” rationale, courts could enforce only those contractual provisions that could have been enacted (30) into general law. Because the Fourteenth Amendment would not have allowed a law that banned members of a certain race from purchasing property, it followed from Shelley’s analysis that judicial enforcement of racially restrictive covenants also was unconstitutional.

(35) Shelley’s attribution logic threatened to dissolve the distinction between state action, to which Fourteenth Amendment limitations apply, and private action, which falls outside of the Fourteenth Amendment’s purview. After all, Shelley’s approach, (40) consistently applied, would require individuals to conform their private agreements to constitutional standards whenever, as is almost always the case, the individuals want the option of later seeking judicial enforcement. Primarily for this reason, neither the (45) Supreme Court nor lower courts later applied Shelley’s approach. Courts routinely enforce contracts whose substantive provisions could not have been constitutionally enacted by government. For instance, courts regularly enforce settlement agreements that (50) limit the settling party’s ability to speak publicly in various respects, despite the fact that statutory limitations on the identical speech would represent an unconstitutional violation of free speech.

Additionally, there is a particularly noxious aspect (55) of the Shelley Court’s analytics—namely, the Court’s conclusion that racially restrictive covenants themselves were perfectly legal. The legal rationale behind the Shelley decision thus failed to target the genuine problem with racially restrictive covenants: (60) what was troubling was not the covenants’ enforcement but their substantive content.

The United States Supreme Court’s 1948 ruling in Shelley v. Kraemer famously disallowed state courts from enforcing racially restrictive covenants. Such covenants are, in essence, private legal obligations (5) included in the deed to a property requiring that only members of a certain race be allowed to occupy the property. Because it prohibited the enforcement of these covenants, the Court’s decision in Shelley v. Kraemer is justly celebrated for overturning a key (10) instrument of housing discrimination. However, while few would deny that racially restrictive covenants are unjust, the stated legal rationale for the Shelley decision has nevertheless proven to be problematic.

The Shelley Court relied on the Fourteenth (15) Amendment to the U.S. Constitution, which grants equal protection under the law to all U.S. citizens. This amendment had long been held to apply to state actors but not individuals. Shelley did not purport to alter this. But where, then, was the state action that is (20) necessary for invoking the Fourteenth Amendment, given that the restrictive covenants were private contracts? The Court’s answer was that although the restrictive covenants themselves were perfectly legal, judicial enforcement of the covenants violated the (25) Fourteenth Amendment because responsibility for a contract’s substantive provisions should be attributed to the state when a court enforces it. According to this “attribution” rationale, courts could enforce only those contractual provisions that could have been enacted (30) into general law. Because the Fourteenth Amendment would not have allowed a law that banned members of a certain race from purchasing property, it followed from Shelley’s analysis that judicial enforcement of racially restrictive covenants also was unconstitutional.

(35) Shelley’s attribution logic threatened to dissolve the distinction between state action, to which Fourteenth Amendment limitations apply, and private action, which falls outside of the Fourteenth Amendment’s purview. After all, Shelley’s approach, (40) consistently applied, would require individuals to conform their private agreements to constitutional standards whenever, as is almost always the case, the individuals want the option of later seeking judicial enforcement. Primarily for this reason, neither the (45) Supreme Court nor lower courts later applied Shelley’s approach. Courts routinely enforce contracts whose substantive provisions could not have been constitutionally enacted by government. For instance, courts regularly enforce settlement agreements that (50) limit the settling party’s ability to speak publicly in various respects, despite the fact that statutory limitations on the identical speech would represent an unconstitutional violation of free speech.

Additionally, there is a particularly noxious aspect (55) of the Shelley Court’s analytics—namely, the Court’s conclusion that racially restrictive covenants themselves were perfectly legal. The legal rationale behind the Shelley decision thus failed to target the genuine problem with racially restrictive covenants: (60) what was troubling was not the covenants’ enforcement but their substantive content.

The United States Supreme Court’s 1948 ruling in Shelley v. Kraemer famously disallowed state courts from enforcing racially restrictive covenants. Such covenants are, in essence, private legal obligations (5) included in the deed to a property requiring that only members of a certain race be allowed to occupy the property. Because it prohibited the enforcement of these covenants, the Court’s decision in Shelley v. Kraemer is justly celebrated for overturning a key (10) instrument of housing discrimination. However, while few would deny that racially restrictive covenants are unjust, the stated legal rationale for the Shelley decision has nevertheless proven to be problematic.

The Shelley Court relied on the Fourteenth (15) Amendment to the U.S. Constitution, which grants equal protection under the law to all U.S. citizens. This amendment had long been held to apply to state actors but not individuals. Shelley did not purport to alter this. But where, then, was the state action that is (20) necessary for invoking the Fourteenth Amendment, given that the restrictive covenants were private contracts? The Court’s answer was that although the restrictive covenants themselves were perfectly legal, judicial enforcement of the covenants violated the (25) Fourteenth Amendment because responsibility for a contract’s substantive provisions should be attributed to the state when a court enforces it. According to this “attribution” rationale, courts could enforce only those contractual provisions that could have been enacted (30) into general law. Because the Fourteenth Amendment would not have allowed a law that banned members of a certain race from purchasing property, it followed from Shelley’s analysis that judicial enforcement of racially restrictive covenants also was unconstitutional.

(35) Shelley’s attribution logic threatened to dissolve the distinction between state action, to which Fourteenth Amendment limitations apply, and private action, which falls outside of the Fourteenth Amendment’s purview. After all, Shelley’s approach, (40) consistently applied, would require individuals to conform their private agreements to constitutional standards whenever, as is almost always the case, the individuals want the option of later seeking judicial enforcement. Primarily for this reason, neither the (45) Supreme Court nor lower courts later applied Shelley’s approach. Courts routinely enforce contracts whose substantive provisions could not have been constitutionally enacted by government. For instance, courts regularly enforce settlement agreements that (50) limit the settling party’s ability to speak publicly in various respects, despite the fact that statutory limitations on the identical speech would represent an unconstitutional violation of free speech.

Additionally, there is a particularly noxious aspect (55) of the Shelley Court’s analytics—namely, the Court’s conclusion that racially restrictive covenants themselves were perfectly legal. The legal rationale behind the Shelley decision thus failed to target the genuine problem with racially restrictive covenants: (60) what was troubling was not the covenants’ enforcement but their substantive content.

Through years of excavations and careful analysis of her finds around Krasnyi Yar in Kazakhstan, archaeologist Sandra Olsen has assembled what may be evidence of the earliest known people to have (5) domesticated and ridden horses, a momentous development in human history. In remains of pit houses of the Botai people, who inhabited this area some 6,000 years ago, are large numbers of bones, 90 percent of them from horses. It is not immediately (10) evident whether the horses were wild or domesticated, because unlike other animals such as dogs and sheep, domestic horses’ bones are not morphologically different from those of their wild counterparts. So Olsen relies heavily on statistical tabulations of the (15) Botai horses by sex and age at death, looking for mortality patterns that might correlate with expectations regarding domesticated herds or wild victims of hunting.

Herders of domesticated animals used for meat or (20) milk typically kill off all but a few males before they are fully mature, but not the females, and archaeologists have evidence of a similar pattern for prehistoric goat herding. At the Botai sites, however, Olsen has found that most of the male horses were fully grown and (25) slightly outnumber the females. One might suppose, then, that they were wild rather than domesticated animals; with many large animal species, hunters would preferentially target adult males so as to maximize size and meat yield. However, it is different (30) with horses. Wild horses live in two types of groups: families consisting of one stallion, six or so adult females, and their young; and bachelor pods consisting of a few males. The families stick together when attacked, but the male groups tend to scatter, so to (35) maximize success in hunting horses, one would target the families. Thus, if the Botai had merely hunted horses, Olsen argues, the proportion of adult male bones should be lower. But if they were in domesticated herds, why were the young males not culled, as would (40) typically occur with, say, herds of goats? Olsen reasons that if the Botai had indeed begun riding, they would likely have kept males alive to ride.

Another clue that at least some of the horses may have been domesticated and that some may have even (45) been ridden is in the fact that their remains include full skeletons, entire vertebral columns, and pelvises. It is unreasonable to suppose that hunters dragged whole 1,000-pound carcasses back to their dwellings. Olsen reasons that these were probably domesticated horses, (50) together with, perhaps, some wild ones hunted and transported using the power of domesticated horses. A number of these nearly whole horse skeletons were discovered buried in a carefully arranged pattern with some of the only human remains yet found in the area, (55) which further suggests a relationship to horses beyond that of merely hunting them as a source of meat.

Through years of excavations and careful analysis of her finds around Krasnyi Yar in Kazakhstan, archaeologist Sandra Olsen has assembled what may be evidence of the earliest known people to have (5) domesticated and ridden horses, a momentous development in human history. In remains of pit houses of the Botai people, who inhabited this area some 6,000 years ago, are large numbers of bones, 90 percent of them from horses. It is not immediately (10) evident whether the horses were wild or domesticated, because unlike other animals such as dogs and sheep, domestic horses’ bones are not morphologically different from those of their wild counterparts. So Olsen relies heavily on statistical tabulations of the (15) Botai horses by sex and age at death, looking for mortality patterns that might correlate with expectations regarding domesticated herds or wild victims of hunting.

Herders of domesticated animals used for meat or (20) milk typically kill off all but a few males before they are fully mature, but not the females, and archaeologists have evidence of a similar pattern for prehistoric goat herding. At the Botai sites, however, Olsen has found that most of the male horses were fully grown and (25) slightly outnumber the females. One might suppose, then, that they were wild rather than domesticated animals; with many large animal species, hunters would preferentially target adult males so as to maximize size and meat yield. However, it is different (30) with horses. Wild horses live in two types of groups: families consisting of one stallion, six or so adult females, and their young; and bachelor pods consisting of a few males. The families stick together when attacked, but the male groups tend to scatter, so to (35) maximize success in hunting horses, one would target the families. Thus, if the Botai had merely hunted horses, Olsen argues, the proportion of adult male bones should be lower. But if they were in domesticated herds, why were the young males not culled, as would (40) typically occur with, say, herds of goats? Olsen reasons that if the Botai had indeed begun riding, they would likely have kept males alive to ride.

Another clue that at least some of the horses may have been domesticated and that some may have even (45) been ridden is in the fact that their remains include full skeletons, entire vertebral columns, and pelvises. It is unreasonable to suppose that hunters dragged whole 1,000-pound carcasses back to their dwellings. Olsen reasons that these were probably domesticated horses, (50) together with, perhaps, some wild ones hunted and transported using the power of domesticated horses. A number of these nearly whole horse skeletons were discovered buried in a carefully arranged pattern with some of the only human remains yet found in the area, (55) which further suggests a relationship to horses beyond that of merely hunting them as a source of meat.

Through years of excavations and careful analysis of her finds around Krasnyi Yar in Kazakhstan, archaeologist Sandra Olsen has assembled what may be evidence of the earliest known people to have (5) domesticated and ridden horses, a momentous development in human history. In remains of pit houses of the Botai people, who inhabited this area some 6,000 years ago, are large numbers of bones, 90 percent of them from horses. It is not immediately (10) evident whether the horses were wild or domesticated, because unlike other animals such as dogs and sheep, domestic horses’ bones are not morphologically different from those of their wild counterparts. So Olsen relies heavily on statistical tabulations of the (15) Botai horses by sex and age at death, looking for mortality patterns that might correlate with expectations regarding domesticated herds or wild victims of hunting.

Herders of domesticated animals used for meat or (20) milk typically kill off all but a few males before they are fully mature, but not the females, and archaeologists have evidence of a similar pattern for prehistoric goat herding. At the Botai sites, however, Olsen has found that most of the male horses were fully grown and (25) slightly outnumber the females. One might suppose, then, that they were wild rather than domesticated animals; with many large animal species, hunters would preferentially target adult males so as to maximize size and meat yield. However, it is different (30) with horses. Wild horses live in two types of groups: families consisting of one stallion, six or so adult females, and their young; and bachelor pods consisting of a few males. The families stick together when attacked, but the male groups tend to scatter, so to (35) maximize success in hunting horses, one would target the families. Thus, if the Botai had merely hunted horses, Olsen argues, the proportion of adult male bones should be lower. But if they were in domesticated herds, why were the young males not culled, as would (40) typically occur with, say, herds of goats? Olsen reasons that if the Botai had indeed begun riding, they would likely have kept males alive to ride.

Another clue that at least some of the horses may have been domesticated and that some may have even (45) been ridden is in the fact that their remains include full skeletons, entire vertebral columns, and pelvises. It is unreasonable to suppose that hunters dragged whole 1,000-pound carcasses back to their dwellings. Olsen reasons that these were probably domesticated horses, (50) together with, perhaps, some wild ones hunted and transported using the power of domesticated horses. A number of these nearly whole horse skeletons were discovered buried in a carefully arranged pattern with some of the only human remains yet found in the area, (55) which further suggests a relationship to horses beyond that of merely hunting them as a source of meat.

Through years of excavations and careful analysis of her finds around Krasnyi Yar in Kazakhstan, archaeologist Sandra Olsen has assembled what may be evidence of the earliest known people to have (5) domesticated and ridden horses, a momentous development in human history. In remains of pit houses of the Botai people, who inhabited this area some 6,000 years ago, are large numbers of bones, 90 percent of them from horses. It is not immediately (10) evident whether the horses were wild or domesticated, because unlike other animals such as dogs and sheep, domestic horses’ bones are not morphologically different from those of their wild counterparts. So Olsen relies heavily on statistical tabulations of the (15) Botai horses by sex and age at death, looking for mortality patterns that might correlate with expectations regarding domesticated herds or wild victims of hunting.

Herders of domesticated animals used for meat or (20) milk typically kill off all but a few males before they are fully mature, but not the females, and archaeologists have evidence of a similar pattern for prehistoric goat herding. At the Botai sites, however, Olsen has found that most of the male horses were fully grown and (25) slightly outnumber the females. One might suppose, then, that they were wild rather than domesticated animals; with many large animal species, hunters would preferentially target adult males so as to maximize size and meat yield. However, it is different (30) with horses. Wild horses live in two types of groups: families consisting of one stallion, six or so adult females, and their young; and bachelor pods consisting of a few males. The families stick together when attacked, but the male groups tend to scatter, so to (35) maximize success in hunting horses, one would target the families. Thus, if the Botai had merely hunted horses, Olsen argues, the proportion of adult male bones should be lower. But if they were in domesticated herds, why were the young males not culled, as would (40) typically occur with, say, herds of goats? Olsen reasons that if the Botai had indeed begun riding, they would likely have kept males alive to ride.

Another clue that at least some of the horses may have been domesticated and that some may have even (45) been ridden is in the fact that their remains include full skeletons, entire vertebral columns, and pelvises. It is unreasonable to suppose that hunters dragged whole 1,000-pound carcasses back to their dwellings. Olsen reasons that these were probably domesticated horses, (50) together with, perhaps, some wild ones hunted and transported using the power of domesticated horses. A number of these nearly whole horse skeletons were discovered buried in a carefully arranged pattern with some of the only human remains yet found in the area, (55) which further suggests a relationship to horses beyond that of merely hunting them as a source of meat.

Through years of excavations and careful analysis of her finds around Krasnyi Yar in Kazakhstan, archaeologist Sandra Olsen has assembled what may be evidence of the earliest known people to have (5) domesticated and ridden horses, a momentous development in human history. In remains of pit houses of the Botai people, who inhabited this area some 6,000 years ago, are large numbers of bones, 90 percent of them from horses. It is not immediately (10) evident whether the horses were wild or domesticated, because unlike other animals such as dogs and sheep, domestic horses’ bones are not morphologically different from those of their wild counterparts. So Olsen relies heavily on statistical tabulations of the (15) Botai horses by sex and age at death, looking for mortality patterns that might correlate with expectations regarding domesticated herds or wild victims of hunting.

Herders of domesticated animals used for meat or (20) milk typically kill off all but a few males before they are fully mature, but not the females, and archaeologists have evidence of a similar pattern for prehistoric goat herding. At the Botai sites, however, Olsen has found that most of the male horses were fully grown and (25) slightly outnumber the females. One might suppose, then, that they were wild rather than domesticated animals; with many large animal species, hunters would preferentially target adult males so as to maximize size and meat yield. However, it is different (30) with horses. Wild horses live in two types of groups: families consisting of one stallion, six or so adult females, and their young; and bachelor pods consisting of a few males. The families stick together when attacked, but the male groups tend to scatter, so to (35) maximize success in hunting horses, one would target the families. Thus, if the Botai had merely hunted horses, Olsen argues, the proportion of adult male bones should be lower. But if they were in domesticated herds, why were the young males not culled, as would (40) typically occur with, say, herds of goats? Olsen reasons that if the Botai had indeed begun riding, they would likely have kept males alive to ride.

Another clue that at least some of the horses may have been domesticated and that some may have even (45) been ridden is in the fact that their remains include full skeletons, entire vertebral columns, and pelvises. It is unreasonable to suppose that hunters dragged whole 1,000-pound carcasses back to their dwellings. Olsen reasons that these were probably domesticated horses, (50) together with, perhaps, some wild ones hunted and transported using the power of domesticated horses. A number of these nearly whole horse skeletons were discovered buried in a carefully arranged pattern with some of the only human remains yet found in the area, (55) which further suggests a relationship to horses beyond that of merely hunting them as a source of meat.

Through years of excavations and careful analysis of her finds around Krasnyi Yar in Kazakhstan, archaeologist Sandra Olsen has assembled what may be evidence of the earliest known people to have (5) domesticated and ridden horses, a momentous development in human history. In remains of pit houses of the Botai people, who inhabited this area some 6,000 years ago, are large numbers of bones, 90 percent of them from horses. It is not immediately (10) evident whether the horses were wild or domesticated, because unlike other animals such as dogs and sheep, domestic horses’ bones are not morphologically different from those of their wild counterparts. So Olsen relies heavily on statistical tabulations of the (15) Botai horses by sex and age at death, looking for mortality patterns that might correlate with expectations regarding domesticated herds or wild victims of hunting.

Herders of domesticated animals used for meat or (20) milk typically kill off all but a few males before they are fully mature, but not the females, and archaeologists have evidence of a similar pattern for prehistoric goat herding. At the Botai sites, however, Olsen has found that most of the male horses were fully grown and (25) slightly outnumber the females. One might suppose, then, that they were wild rather than domesticated animals; with many large animal species, hunters would preferentially target adult males so as to maximize size and meat yield. However, it is different (30) with horses. Wild horses live in two types of groups: families consisting of one stallion, six or so adult females, and their young; and bachelor pods consisting of a few males. The families stick together when attacked, but the male groups tend to scatter, so to (35) maximize success in hunting horses, one would target the families. Thus, if the Botai had merely hunted horses, Olsen argues, the proportion of adult male bones should be lower. But if they were in domesticated herds, why were the young males not culled, as would (40) typically occur with, say, herds of goats? Olsen reasons that if the Botai had indeed begun riding, they would likely have kept males alive to ride.

Another clue that at least some of the horses may have been domesticated and that some may have even (45) been ridden is in the fact that their remains include full skeletons, entire vertebral columns, and pelvises. It is unreasonable to suppose that hunters dragged whole 1,000-pound carcasses back to their dwellings. Olsen reasons that these were probably domesticated horses, (50) together with, perhaps, some wild ones hunted and transported using the power of domesticated horses. A number of these nearly whole horse skeletons were discovered buried in a carefully arranged pattern with some of the only human remains yet found in the area, (55) which further suggests a relationship to horses beyond that of merely hunting them as a source of meat.

Through years of excavations and careful analysis of her finds around Krasnyi Yar in Kazakhstan, archaeologist Sandra Olsen has assembled what may be evidence of the earliest known people to have (5) domesticated and ridden horses, a momentous development in human history. In remains of pit houses of the Botai people, who inhabited this area some 6,000 years ago, are large numbers of bones, 90 percent of them from horses. It is not immediately (10) evident whether the horses were wild or domesticated, because unlike other animals such as dogs and sheep, domestic horses’ bones are not morphologically different from those of their wild counterparts. So Olsen relies heavily on statistical tabulations of the (15) Botai horses by sex and age at death, looking for mortality patterns that might correlate with expectations regarding domesticated herds or wild victims of hunting.

Herders of domesticated animals used for meat or (20) milk typically kill off all but a few males before they are fully mature, but not the females, and archaeologists have evidence of a similar pattern for prehistoric goat herding. At the Botai sites, however, Olsen has found that most of the male horses were fully grown and (25) slightly outnumber the females. One might suppose, then, that they were wild rather than domesticated animals; with many large animal species, hunters would preferentially target adult males so as to maximize size and meat yield. However, it is different (30) with horses. Wild horses live in two types of groups: families consisting of one stallion, six or so adult females, and their young; and bachelor pods consisting of a few males. The families stick together when attacked, but the male groups tend to scatter, so to (35) maximize success in hunting horses, one would target the families. Thus, if the Botai had merely hunted horses, Olsen argues, the proportion of adult male bones should be lower. But if they were in domesticated herds, why were the young males not culled, as would (40) typically occur with, say, herds of goats? Olsen reasons that if the Botai had indeed begun riding, they would likely have kept males alive to ride.

Another clue that at least some of the horses may have been domesticated and that some may have even (45) been ridden is in the fact that their remains include full skeletons, entire vertebral columns, and pelvises. It is unreasonable to suppose that hunters dragged whole 1,000-pound carcasses back to their dwellings. Olsen reasons that these were probably domesticated horses, (50) together with, perhaps, some wild ones hunted and transported using the power of domesticated horses. A number of these nearly whole horse skeletons were discovered buried in a carefully arranged pattern with some of the only human remains yet found in the area, (55) which further suggests a relationship to horses beyond that of merely hunting them as a source of meat.

Through years of excavations and careful analysis of her finds around Krasnyi Yar in Kazakhstan, archaeologist Sandra Olsen has assembled what may be evidence of the earliest known people to have (5) domesticated and ridden horses, a momentous development in human history. In remains of pit houses of the Botai people, who inhabited this area some 6,000 years ago, are large numbers of bones, 90 percent of them from horses. It is not immediately (10) evident whether the horses were wild or domesticated, because unlike other animals such as dogs and sheep, domestic horses’ bones are not morphologically different from those of their wild counterparts. So Olsen relies heavily on statistical tabulations of the (15) Botai horses by sex and age at death, looking for mortality patterns that might correlate with expectations regarding domesticated herds or wild victims of hunting.

Herders of domesticated animals used for meat or (20) milk typically kill off all but a few males before they are fully mature, but not the females, and archaeologists have evidence of a similar pattern for prehistoric goat herding. At the Botai sites, however, Olsen has found that most of the male horses were fully grown and (25) slightly outnumber the females. One might suppose, then, that they were wild rather than domesticated animals; with many large animal species, hunters would preferentially target adult males so as to maximize size and meat yield. However, it is different (30) with horses. Wild horses live in two types of groups: families consisting of one stallion, six or so adult females, and their young; and bachelor pods consisting of a few males. The families stick together when attacked, but the male groups tend to scatter, so to (35) maximize success in hunting horses, one would target the families. Thus, if the Botai had merely hunted horses, Olsen argues, the proportion of adult male bones should be lower. But if they were in domesticated herds, why were the young males not culled, as would (40) typically occur with, say, herds of goats? Olsen reasons that if the Botai had indeed begun riding, they would likely have kept males alive to ride.

Another clue that at least some of the horses may have been domesticated and that some may have even (45) been ridden is in the fact that their remains include full skeletons, entire vertebral columns, and pelvises. It is unreasonable to suppose that hunters dragged whole 1,000-pound carcasses back to their dwellings. Olsen reasons that these were probably domesticated horses, (50) together with, perhaps, some wild ones hunted and transported using the power of domesticated horses. A number of these nearly whole horse skeletons were discovered buried in a carefully arranged pattern with some of the only human remains yet found in the area, (55) which further suggests a relationship to horses beyond that of merely hunting them as a source of meat.

Passage A

Music does not always gain by association with words. Like images, words can excite the deepest emotions but are inadequate to express the emotions (5) they excite. Music is more adequate, and hence will often seize an emotion that may have been excited by images or words, deepen its expression, and, by so doing, excite still deeper emotion. That is how words can gain by being set to music.

(10) But to set words to music—as in opera or song— is in fact to mix two arts together. A striking effect may be produced, but at the expense of the purity of each art. Poetry is a great art; so is music. But as a medium for emotion, each is greater alone than in (15) company, although various good ends arise from linking the two, providing that the words are subordinated to the more expressive medium of music. What good could any words do for Beethoven’s Fifth Symphony? So too an opera is largely independent of (20) words, and depends for its aesthetic value not upon the poetry of the libretto words of the opera), or even the plot or scenery, but upon its emotional range—a region dominated by the musical element.

Passage B

(25) Throughout the history of opera, two fundamental types may be distinguished: that in which the music is primary, and that in which there is, essentially, parity between music and other factors. The former, sometimes called “singer’s opera”—a term which has (30) earned undeserved contempt—is exemplified by most Italian operas, while the latter, exemplified by the operas of German composer Richard Wagner, depend for their effect on a balance among many factors of which music is only one, albeit the most important. (35) Theoretically, it would seem that there should be a third kind of opera, in which the music is subordinated to the other features. While the earliest operas were of this kind, their appeal was limited, and a fuller participation of music was required to establish opera (40) on a secure basis.

In any event, in any aesthetic judgment of opera, regardless of the opera’s type, neither the music nor the poetry of the libretto should be judged in isolation. The music is good not if it would make a good concert (45) piece but if it serves the particular situation in the opera in which it occurs, contributing something not supplied by other elements. Similarly, the poetry is good not because it reads well by itself but primarily if, while embodying a sound dramatic idea, it furnishes (50) opportunity for effective musical and scenic treatment. True, the elements of music and poetry may be considered separately, but only for purposes of analyzing their formal features. In actuality these elements are as united as hydrogen and oxygen are (55) united in water. It is this union—further enriched and clarified by the visual action—that results in opera’s inimitable character.

Passage A

Music does not always gain by association with words. Like images, words can excite the deepest emotions but are inadequate to express the emotions (5) they excite. Music is more adequate, and hence will often seize an emotion that may have been excited by images or words, deepen its expression, and, by so doing, excite still deeper emotion. That is how words can gain by being set to music.

(10) But to set words to music—as in opera or song— is in fact to mix two arts together. A striking effect may be produced, but at the expense of the purity of each art. Poetry is a great art; so is music. But as a medium for emotion, each is greater alone than in (15) company, although various good ends arise from linking the two, providing that the words are subordinated to the more expressive medium of music. What good could any words do for Beethoven’s Fifth Symphony? So too an opera is largely independent of (20) words, and depends for its aesthetic value not upon the poetry of the libretto words of the opera), or even the plot or scenery, but upon its emotional range—a region dominated by the musical element.

Passage B

(25) Throughout the history of opera, two fundamental types may be distinguished: that in which the music is primary, and that in which there is, essentially, parity between music and other factors. The former, sometimes called “singer’s opera”—a term which has (30) earned undeserved contempt—is exemplified by most Italian operas, while the latter, exemplified by the operas of German composer Richard Wagner, depend for their effect on a balance among many factors of which music is only one, albeit the most important. (35) Theoretically, it would seem that there should be a third kind of opera, in which the music is subordinated to the other features. While the earliest operas were of this kind, their appeal was limited, and a fuller participation of music was required to establish opera (40) on a secure basis.

In any event, in any aesthetic judgment of opera, regardless of the opera’s type, neither the music nor the poetry of the libretto should be judged in isolation. The music is good not if it would make a good concert (45) piece but if it serves the particular situation in the opera in which it occurs, contributing something not supplied by other elements. Similarly, the poetry is good not because it reads well by itself but primarily if, while embodying a sound dramatic idea, it furnishes (50) opportunity for effective musical and scenic treatment. True, the elements of music and poetry may be considered separately, but only for purposes of analyzing their formal features. In actuality these elements are as united as hydrogen and oxygen are (55) united in water. It is this union—further enriched and clarified by the visual action—that results in opera’s inimitable character.

Passage A

Music does not always gain by association with words. Like images, words can excite the deepest emotions but are inadequate to express the emotions (5) they excite. Music is more adequate, and hence will often seize an emotion that may have been excited by images or words, deepen its expression, and, by so doing, excite still deeper emotion. That is how words can gain by being set to music.

(10) But to set words to music—as in opera or song— is in fact to mix two arts together. A striking effect may be produced, but at the expense of the purity of each art. Poetry is a great art; so is music. But as a medium for emotion, each is greater alone than in (15) company, although various good ends arise from linking the two, providing that the words are subordinated to the more expressive medium of music. What good could any words do for Beethoven’s Fifth Symphony? So too an opera is largely independent of (20) words, and depends for its aesthetic value not upon the poetry of the libretto words of the opera), or even the plot or scenery, but upon its emotional range—a region dominated by the musical element.

Passage B

(25) Throughout the history of opera, two fundamental types may be distinguished: that in which the music is primary, and that in which there is, essentially, parity between music and other factors. The former, sometimes called “singer’s opera”—a term which has (30) earned undeserved contempt—is exemplified by most Italian operas, while the latter, exemplified by the operas of German composer Richard Wagner, depend for their effect on a balance among many factors of which music is only one, albeit the most important. (35) Theoretically, it would seem that there should be a third kind of opera, in which the music is subordinated to the other features. While the earliest operas were of this kind, their appeal was limited, and a fuller participation of music was required to establish opera (40) on a secure basis.

In any event, in any aesthetic judgment of opera, regardless of the opera’s type, neither the music nor the poetry of the libretto should be judged in isolation. The music is good not if it would make a good concert (45) piece but if it serves the particular situation in the opera in which it occurs, contributing something not supplied by other elements. Similarly, the poetry is good not because it reads well by itself but primarily if, while embodying a sound dramatic idea, it furnishes (50) opportunity for effective musical and scenic treatment. True, the elements of music and poetry may be considered separately, but only for purposes of analyzing their formal features. In actuality these elements are as united as hydrogen and oxygen are (55) united in water. It is this union—further enriched and clarified by the visual action—that results in opera’s inimitable character.

Passage A

Music does not always gain by association with words. Like images, words can excite the deepest emotions but are inadequate to express the emotions (5) they excite. Music is more adequate, and hence will often seize an emotion that may have been excited by images or words, deepen its expression, and, by so doing, excite still deeper emotion. That is how words can gain by being set to music.

(10) But to set words to music—as in opera or song— is in fact to mix two arts together. A striking effect may be produced, but at the expense of the purity of each art. Poetry is a great art; so is music. But as a medium for emotion, each is greater alone than in (15) company, although various good ends arise from linking the two, providing that the words are subordinated to the more expressive medium of music. What good could any words do for Beethoven’s Fifth Symphony? So too an opera is largely independent of (20) words, and depends for its aesthetic value not upon the poetry of the libretto words of the opera), or even the plot or scenery, but upon its emotional range—a region dominated by the musical element.

Passage B

(25) Throughout the history of opera, two fundamental types may be distinguished: that in which the music is primary, and that in which there is, essentially, parity between music and other factors. The former, sometimes called “singer’s opera”—a term which has (30) earned undeserved contempt—is exemplified by most Italian operas, while the latter, exemplified by the operas of German composer Richard Wagner, depend for their effect on a balance among many factors of which music is only one, albeit the most important. (35) Theoretically, it would seem that there should be a third kind of opera, in which the music is subordinated to the other features. While the earliest operas were of this kind, their appeal was limited, and a fuller participation of music was required to establish opera (40) on a secure basis.

In any event, in any aesthetic judgment of opera, regardless of the opera’s type, neither the music nor the poetry of the libretto should be judged in isolation. The music is good not if it would make a good concert (45) piece but if it serves the particular situation in the opera in which it occurs, contributing something not supplied by other elements. Similarly, the poetry is good not because it reads well by itself but primarily if, while embodying a sound dramatic idea, it furnishes (50) opportunity for effective musical and scenic treatment. True, the elements of music and poetry may be considered separately, but only for purposes of analyzing their formal features. In actuality these elements are as united as hydrogen and oxygen are (55) united in water. It is this union—further enriched and clarified by the visual action—that results in opera’s inimitable character.

Passage A

Music does not always gain by association with words. Like images, words can excite the deepest emotions but are inadequate to express the emotions (5) they excite. Music is more adequate, and hence will often seize an emotion that may have been excited by images or words, deepen its expression, and, by so doing, excite still deeper emotion. That is how words can gain by being set to music.

(10) But to set words to music—as in opera or song— is in fact to mix two arts together. A striking effect may be produced, but at the expense of the purity of each art. Poetry is a great art; so is music. But as a medium for emotion, each is greater alone than in (15) company, although various good ends arise from linking the two, providing that the words are subordinated to the more expressive medium of music. What good could any words do for Beethoven’s Fifth Symphony? So too an opera is largely independent of (20) words, and depends for its aesthetic value not upon the poetry of the libretto words of the opera), or even the plot or scenery, but upon its emotional range—a region dominated by the musical element.

Passage B

(25) Throughout the history of opera, two fundamental types may be distinguished: that in which the music is primary, and that in which there is, essentially, parity between music and other factors. The former, sometimes called “singer’s opera”—a term which has (30) earned undeserved contempt—is exemplified by most Italian operas, while the latter, exemplified by the operas of German composer Richard Wagner, depend for their effect on a balance among many factors of which music is only one, albeit the most important. (35) Theoretically, it would seem that there should be a third kind of opera, in which the music is subordinated to the other features. While the earliest operas were of this kind, their appeal was limited, and a fuller participation of music was required to establish opera (40) on a secure basis.

In any event, in any aesthetic judgment of opera, regardless of the opera’s type, neither the music nor the poetry of the libretto should be judged in isolation. The music is good not if it would make a good concert (45) piece but if it serves the particular situation in the opera in which it occurs, contributing something not supplied by other elements. Similarly, the poetry is good not because it reads well by itself but primarily if, while embodying a sound dramatic idea, it furnishes (50) opportunity for effective musical and scenic treatment. True, the elements of music and poetry may be considered separately, but only for purposes of analyzing their formal features. In actuality these elements are as united as hydrogen and oxygen are (55) united in water. It is this union—further enriched and clarified by the visual action—that results in opera’s inimitable character.

Passage A

Music does not always gain by association with words. Like images, words can excite the deepest emotions but are inadequate to express the emotions (5) they excite. Music is more adequate, and hence will often seize an emotion that may have been excited by images or words, deepen its expression, and, by so doing, excite still deeper emotion. That is how words can gain by being set to music.

(10) But to set words to music—as in opera or song— is in fact to mix two arts together. A striking effect may be produced, but at the expense of the purity of each art. Poetry is a great art; so is music. But as a medium for emotion, each is greater alone than in (15) company, although various good ends arise from linking the two, providing that the words are subordinated to the more expressive medium of music. What good could any words do for Beethoven’s Fifth Symphony? So too an opera is largely independent of (20) words, and depends for its aesthetic value not upon the poetry of the libretto words of the opera), or even the plot or scenery, but upon its emotional range—a region dominated by the musical element.

Passage B

(25) Throughout the history of opera, two fundamental types may be distinguished: that in which the music is primary, and that in which there is, essentially, parity between music and other factors. The former, sometimes called “singer’s opera”—a term which has (30) earned undeserved contempt—is exemplified by most Italian operas, while the latter, exemplified by the operas of German composer Richard Wagner, depend for their effect on a balance among many factors of which music is only one, albeit the most important. (35) Theoretically, it would seem that there should be a third kind of opera, in which the music is subordinated to the other features. While the earliest operas were of this kind, their appeal was limited, and a fuller participation of music was required to establish opera (40) on a secure basis.

In any event, in any aesthetic judgment of opera, regardless of the opera’s type, neither the music nor the poetry of the libretto should be judged in isolation. The music is good not if it would make a good concert (45) piece but if it serves the particular situation in the opera in which it occurs, contributing something not supplied by other elements. Similarly, the poetry is good not because it reads well by itself but primarily if, while embodying a sound dramatic idea, it furnishes (50) opportunity for effective musical and scenic treatment. True, the elements of music and poetry may be considered separately, but only for purposes of analyzing their formal features. In actuality these elements are as united as hydrogen and oxygen are (55) united in water. It is this union—further enriched and clarified by the visual action—that results in opera’s inimitable character.

Passage A

Music does not always gain by association with words. Like images, words can excite the deepest emotions but are inadequate to express the emotions (5) they excite. Music is more adequate, and hence will often seize an emotion that may have been excited by images or words, deepen its expression, and, by so doing, excite still deeper emotion. That is how words can gain by being set to music.

(10) But to set words to music—as in opera or song— is in fact to mix two arts together. A striking effect may be produced, but at the expense of the purity of each art. Poetry is a great art; so is music. But as a medium for emotion, each is greater alone than in (15) company, although various good ends arise from linking the two, providing that the words are subordinated to the more expressive medium of music. What good could any words do for Beethoven’s Fifth Symphony? So too an opera is largely independent of (20) words, and depends for its aesthetic value not upon the poetry of the libretto words of the opera), or even the plot or scenery, but upon its emotional range—a region dominated by the musical element.

Passage B

(25) Throughout the history of opera, two fundamental types may be distinguished: that in which the music is primary, and that in which there is, essentially, parity between music and other factors. The former, sometimes called “singer’s opera”—a term which has (30) earned undeserved contempt—is exemplified by most Italian operas, while the latter, exemplified by the operas of German composer Richard Wagner, depend for their effect on a balance among many factors of which music is only one, albeit the most important. (35) Theoretically, it would seem that there should be a third kind of opera, in which the music is subordinated to the other features. While the earliest operas were of this kind, their appeal was limited, and a fuller participation of music was required to establish opera (40) on a secure basis.

In any event, in any aesthetic judgment of opera, regardless of the opera’s type, neither the music nor the poetry of the libretto should be judged in isolation. The music is good not if it would make a good concert (45) piece but if it serves the particular situation in the opera in which it occurs, contributing something not supplied by other elements. Similarly, the poetry is good not because it reads well by itself but primarily if, while embodying a sound dramatic idea, it furnishes (50) opportunity for effective musical and scenic treatment. True, the elements of music and poetry may be considered separately, but only for purposes of analyzing their formal features. In actuality these elements are as united as hydrogen and oxygen are (55) united in water. It is this union—further enriched and clarified by the visual action—that results in opera’s inimitable character.

According to the generally accepted theory of plate tectonics, the earth’s crust consists of a dozen or so plates of solid rock moving across the mantle—the slightly fluid layer of rock between crust and core. (5) Most earthquakes can' then be explained as a result of the grinding of these plates against one another as they collide. When two plates collide, one plate is forced under the other until it eventually merges with the . underlying mantle. According to this explanation, this (10) process, called subduction, causes an enormous build-up of energy that is abruptly released in the form of an earthquake. Most earthquakes take place in the earth’s seismic “hot zones’’—regions with very high levels of subduction. Contrary to expectations, (15) however, global seismic data indicate that there are also regions with high levels of subduction that are nonetheless nearly free of earthquakes. Thus, until recently, there remained a crucial question for which the plate tectonics theory had no answer—how can (20) often intense subduction take place at certain locations with little or no seismic effect?

One group of scientists now proposes that the relative quiet of these zones is tied to the nature of the collision between the plates. In many seismic hot zones, (25) the plates exhibit motion in opposite directions— that is, they collide because they are moving toward each other. And because the two plates are moving in opposite directions, the subduction zone is relatively motionless relative to the underlying mantle. In (30) contrast, the plate collisions in the quiet subduction zones occur between two plates that are moving in the same general direction—the second plate’s motion is simply faster than that of the first, and its leading edge therefore becomes subducted. But in this type of (35) subduction, the collision zone moves with a comparatively high velocity relative to the mantle below. Thus, rather like an oar dipped into the water from a moving boat, the overtaking plate encounters great resistance from the mantle and is forced to (40) descend steeply as it is absorbed into the mantle. The steep descent of the overtaking plate in this type of collision reduces the amount of contact between the two plates, and the earthquake-producing friction is thereby reduced as well. On the other hand, in (45) collisions in which the plates move toward each other the subducted plate receives relatively little resistance from the mantle, and so its angle of descent is correspondingly shallow, allowing for a much larger plane of contact between the two plates. Like two (50) sheets of sandpaper pressed together, these plates offer each other a great deal of resistance.

This proposal also provides a warning. It suggests that regions that were previously thought to be seismically innocuous—regions with low levels of (55) subduction—may in fact be at a significant risk of earthquakes, depending on the nature of the subduction taking place.

According to the generally accepted theory of plate tectonics, the earth’s crust consists of a dozen or so plates of solid rock moving across the mantle—the slightly fluid layer of rock between crust and core. (5) Most earthquakes can' then be explained as a result of the grinding of these plates against one another as they collide. When two plates collide, one plate is forced under the other until it eventually merges with the . underlying mantle. According to this explanation, this (10) process, called subduction, causes an enormous build-up of energy that is abruptly released in the form of an earthquake. Most earthquakes take place in the earth’s seismic “hot zones’’—regions with very high levels of subduction. Contrary to expectations, (15) however, global seismic data indicate that there are also regions with high levels of subduction that are nonetheless nearly free of earthquakes. Thus, until recently, there remained a crucial question for which the plate tectonics theory had no answer—how can (20) often intense subduction take place at certain locations with little or no seismic effect?

One group of scientists now proposes that the relative quiet of these zones is tied to the nature of the collision between the plates. In many seismic hot zones, (25) the plates exhibit motion in opposite directions— that is, they collide because they are moving toward each other. And because the two plates are moving in opposite directions, the subduction zone is relatively motionless relative to the underlying mantle. In (30) contrast, the plate collisions in the quiet subduction zones occur between two plates that are moving in the same general direction—the second plate’s motion is simply faster than that of the first, and its leading edge therefore becomes subducted. But in this type of (35) subduction, the collision zone moves with a comparatively high velocity relative to the mantle below. Thus, rather like an oar dipped into the water from a moving boat, the overtaking plate encounters great resistance from the mantle and is forced to (40) descend steeply as it is absorbed into the mantle. The steep descent of the overtaking plate in this type of collision reduces the amount of contact between the two plates, and the earthquake-producing friction is thereby reduced as well. On the other hand, in (45) collisions in which the plates move toward each other the subducted plate receives relatively little resistance from the mantle, and so its angle of descent is correspondingly shallow, allowing for a much larger plane of contact between the two plates. Like two (50) sheets of sandpaper pressed together, these plates offer each other a great deal of resistance.

This proposal also provides a warning. It suggests that regions that were previously thought to be seismically innocuous—regions with low levels of (55) subduction—may in fact be at a significant risk of earthquakes, depending on the nature of the subduction taking place.

According to the generally accepted theory of plate tectonics, the earth’s crust consists of a dozen or so plates of solid rock moving across the mantle—the slightly fluid layer of rock between crust and core. (5) Most earthquakes can' then be explained as a result of the grinding of these plates against one another as they collide. When two plates collide, one plate is forced under the other until it eventually merges with the . underlying mantle. According to this explanation, this (10) process, called subduction, causes an enormous build-up of energy that is abruptly released in the form of an earthquake. Most earthquakes take place in the earth’s seismic “hot zones’’—regions with very high levels of subduction. Contrary to expectations, (15) however, global seismic data indicate that there are also regions with high levels of subduction that are nonetheless nearly free of earthquakes. Thus, until recently, there remained a crucial question for which the plate tectonics theory had no answer—how can (20) often intense subduction take place at certain locations with little or no seismic effect?

One group of scientists now proposes that the relative quiet of these zones is tied to the nature of the collision between the plates. In many seismic hot zones, (25) the plates exhibit motion in opposite directions— that is, they collide because they are moving toward each other. And because the two plates are moving in opposite directions, the subduction zone is relatively motionless relative to the underlying mantle. In (30) contrast, the plate collisions in the quiet subduction zones occur between two plates that are moving in the same general direction—the second plate’s motion is simply faster than that of the first, and its leading edge therefore becomes subducted. But in this type of (35) subduction, the collision zone moves with a comparatively high velocity relative to the mantle below. Thus, rather like an oar dipped into the water from a moving boat, the overtaking plate encounters great resistance from the mantle and is forced to (40) descend steeply as it is absorbed into the mantle. The steep descent of the overtaking plate in this type of collision reduces the amount of contact between the two plates, and the earthquake-producing friction is thereby reduced as well. On the other hand, in (45) collisions in which the plates move toward each other the subducted plate receives relatively little resistance from the mantle, and so its angle of descent is correspondingly shallow, allowing for a much larger plane of contact between the two plates. Like two (50) sheets of sandpaper pressed together, these plates offer each other a great deal of resistance.

This proposal also provides a warning. It suggests that regions that were previously thought to be seismically innocuous—regions with low levels of (55) subduction—may in fact be at a significant risk of earthquakes, depending on the nature of the subduction taking place.

According to the generally accepted theory of plate tectonics, the earth’s crust consists of a dozen or so plates of solid rock moving across the mantle—the slightly fluid layer of rock between crust and core. (5) Most earthquakes can' then be explained as a result of the grinding of these plates against one another as they collide. When two plates collide, one plate is forced under the other until it eventually merges with the . underlying mantle. According to this explanation, this (10) process, called subduction, causes an enormous build-up of energy that is abruptly released in the form of an earthquake. Most earthquakes take place in the earth’s seismic “hot zones’’—regions with very high levels of subduction. Contrary to expectations, (15) however, global seismic data indicate that there are also regions with high levels of subduction that are nonetheless nearly free of earthquakes. Thus, until recently, there remained a crucial question for which the plate tectonics theory had no answer—how can (20) often intense subduction take place at certain locations with little or no seismic effect?

One group of scientists now proposes that the relative quiet of these zones is tied to the nature of the collision between the plates. In many seismic hot zones, (25) the plates exhibit motion in opposite directions— that is, they collide because they are moving toward each other. And because the two plates are moving in opposite directions, the subduction zone is relatively motionless relative to the underlying mantle. In (30) contrast, the plate collisions in the quiet subduction zones occur between two plates that are moving in the same general direction—the second plate’s motion is simply faster than that of the first, and its leading edge therefore becomes subducted. But in this type of (35) subduction, the collision zone moves with a comparatively high velocity relative to the mantle below. Thus, rather like an oar dipped into the water from a moving boat, the overtaking plate encounters great resistance from the mantle and is forced to (40) descend steeply as it is absorbed into the mantle. The steep descent of the overtaking plate in this type of collision reduces the amount of contact between the two plates, and the earthquake-producing friction is thereby reduced as well. On the other hand, in (45) collisions in which the plates move toward each other the subducted plate receives relatively little resistance from the mantle, and so its angle of descent is correspondingly shallow, allowing for a much larger plane of contact between the two plates. Like two (50) sheets of sandpaper pressed together, these plates offer each other a great deal of resistance.

This proposal also provides a warning. It suggests that regions that were previously thought to be seismically innocuous—regions with low levels of (55) subduction—may in fact be at a significant risk of earthquakes, depending on the nature of the subduction taking place.

According to the generally accepted theory of plate tectonics, the earth’s crust consists of a dozen or so plates of solid rock moving across the mantle—the slightly fluid layer of rock between crust and core. (5) Most earthquakes can' then be explained as a result of the grinding of these plates against one another as they collide. When two plates collide, one plate is forced under the other until it eventually merges with the . underlying mantle. According to this explanation, this (10) process, called subduction, causes an enormous build-up of energy that is abruptly released in the form of an earthquake. Most earthquakes take place in the earth’s seismic “hot zones’’—regions with very high levels of subduction. Contrary to expectations, (15) however, global seismic data indicate that there are also regions with high levels of subduction that are nonetheless nearly free of earthquakes. Thus, until recently, there remained a crucial question for which the plate tectonics theory had no answer—how can (20) often intense subduction take place at certain locations with little or no seismic effect?

One group of scientists now proposes that the relative quiet of these zones is tied to the nature of the collision between the plates. In many seismic hot zones, (25) the plates exhibit motion in opposite directions— that is, they collide because they are moving toward each other. And because the two plates are moving in opposite directions, the subduction zone is relatively motionless relative to the underlying mantle. In (30) contrast, the plate collisions in the quiet subduction zones occur between two plates that are moving in the same general direction—the second plate’s motion is simply faster than that of the first, and its leading edge therefore becomes subducted. But in this type of (35) subduction, the collision zone moves with a comparatively high velocity relative to the mantle below. Thus, rather like an oar dipped into the water from a moving boat, the overtaking plate encounters great resistance from the mantle and is forced to (40) descend steeply as it is absorbed into the mantle. The steep descent of the overtaking plate in this type of collision reduces the amount of contact between the two plates, and the earthquake-producing friction is thereby reduced as well. On the other hand, in (45) collisions in which the plates move toward each other the subducted plate receives relatively little resistance from the mantle, and so its angle of descent is correspondingly shallow, allowing for a much larger plane of contact between the two plates. Like two (50) sheets of sandpaper pressed together, these plates offer each other a great deal of resistance.

This proposal also provides a warning. It suggests that regions that were previously thought to be seismically innocuous—regions with low levels of (55) subduction—may in fact be at a significant risk of earthquakes, depending on the nature of the subduction taking place.

According to the generally accepted theory of plate tectonics, the earth’s crust consists of a dozen or so plates of solid rock moving across the mantle—the slightly fluid layer of rock between crust and core. (5) Most earthquakes can' then be explained as a result of the grinding of these plates against one another as they collide. When two plates collide, one plate is forced under the other until it eventually merges with the . underlying mantle. According to this explanation, this (10) process, called subduction, causes an enormous build-up of energy that is abruptly released in the form of an earthquake. Most earthquakes take place in the earth’s seismic “hot zones’’—regions with very high levels of subduction. Contrary to expectations, (15) however, global seismic data indicate that there are also regions with high levels of subduction that are nonetheless nearly free of earthquakes. Thus, until recently, there remained a crucial question for which the plate tectonics theory had no answer—how can (20) often intense subduction take place at certain locations with little or no seismic effect?

One group of scientists now proposes that the relative quiet of these zones is tied to the nature of the collision between the plates. In many seismic hot zones, (25) the plates exhibit motion in opposite directions— that is, they collide because they are moving toward each other. And because the two plates are moving in opposite directions, the subduction zone is relatively motionless relative to the underlying mantle. In (30) contrast, the plate collisions in the quiet subduction zones occur between two plates that are moving in the same general direction—the second plate’s motion is simply faster than that of the first, and its leading edge therefore becomes subducted. But in this type of (35) subduction, the collision zone moves with a comparatively high velocity relative to the mantle below. Thus, rather like an oar dipped into the water from a moving boat, the overtaking plate encounters great resistance from the mantle and is forced to (40) descend steeply as it is absorbed into the mantle. The steep descent of the overtaking plate in this type of collision reduces the amount of contact between the two plates, and the earthquake-producing friction is thereby reduced as well. On the other hand, in (45) collisions in which the plates move toward each other the subducted plate receives relatively little resistance from the mantle, and so its angle of descent is correspondingly shallow, allowing for a much larger plane of contact between the two plates. Like two (50) sheets of sandpaper pressed together, these plates offer each other a great deal of resistance.

This proposal also provides a warning. It suggests that regions that were previously thought to be seismically innocuous—regions with low levels of (55) subduction—may in fact be at a significant risk of earthquakes, depending on the nature of the subduction taking place.