Crustal structure of Oaxaca, Mexico, from seismic refraction measurements
Crustal structure of Oaxaca, Mexico, from seismic refraction measurements
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墨西哥瓦哈卡州的地壳结构，来自地震折射测量
DOI：
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发表时间：
1986
期刊：
影响因子：
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通讯作者：
M. Mena
中科院分区：
文献类型：
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作者：
C. Valdés;W. Mooney;S. K. Singh;R. Meyer;C. Lomnitz;J. Luetgert;C. Helsley;B. Lewis;M. Mena
对地震折射和重力数据进行了分析，得到了墨西哥西南部瓦哈卡州海洋向大陆过渡的纵波结构模型。根据莫霍面的反射相位计算，北纬18°的大陆地壳厚度为45_4公里。地壳被模拟为三层，速度分别为4.3~4.6，5.0~5.7，6.85~7.0公里/秒，每一层都具有正速度梯度。在皮诺特帕国家公园附近的海岸，地壳变薄到10公里，那里的前寒武纪变质岩暴露在距离美洲中部海沟45公里的地方。在近海，海洋结构由8公里厚的地壳组成，具有正常的地壳速度结构(Spudich和Orutt，1980)。墨西哥西部俯冲板块的视倾角为10°，在海洋一侧，强反射表明岩石圈-软流圈边界的最小深度为35公里。软流圈的地震速度为7.6公里/秒，有一个薄盖，其速度为8.6公里/秒。
Seismic refraction and gravity data have been analyzed to obtain a model of the compressional-wave structure of the ocean-to-continent transition in the State of Oaxaca in southwestern Mexico. Crustal thickness on the continent at the latitude 18°N is 45 _ 4 km, based on reflected phases from the Moho discontinuity. The crust has been modeled with three layers, with velocities of 4.3 to 4.6, 5.0 to 5.7, and 6.85 to 7.0 km/sec, each with positive velocity gradient. The crust thins to 10 km at the coast near Pinotepa Nacional, where Precambrian metamorphic rocks are exposed 45 km from the mid-America trench. Offshore, the oceanic structure consists of an 8-km-thick crust with a normal crustal velocity structure (Spudich and Orcutt, 1980). The apparent dip of the subducting plate beneath western Mexico is 10 °, On the oceanic side, strong reflections suggest a minimum depth of 35 km for the lithosphere-asthenosphere boundary. The asthenosphere has a seismic velocity of 7.6 km/sec, and a thin lid in which the velocity is 8.6 km/sec.