Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico
Seismicity recorded from June 1994 to May 1995 on a portable network of analog and digital seismic stations defines the geometry of the Wadati-Benioff zone under Chiapas and the distributions of the principal stresses along the subducted slab. Seismicity at the outer-rise region is not well located....
| Autores: | , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1999 |
| País: | México |
| Institución: | UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO |
| Repositorio: | Geofísica Internacional |
| Idioma: | español |
| OAI Identifier: | oai:revistagi.geofisica.unam.mx:article/635 |
| Acceso en línea: | http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/635 |
| Access Level: | acceso abierto |
| Palabra clave: | Sismicidad zona de Wadati-Benioff mecanismos focales distribución de esfuerzos Seismicity Wadati-Benioff zone focal mechanisms stress distribution |
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Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, MexicoDistributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, MexicoRebollar, Cecilio J.Espíndola, Víctor H.Uribe, AntonioMendoza, AntonioPérez-Vertti, ArturoSismicidadzona de Wadati-Benioffmecanismos focalesdistribución de esfuerzosSeismicityWadati-Benioff zonefocal mechanismsstress distributionSeismicity recorded from June 1994 to May 1995 on a portable network of analog and digital seismic stations defines the geometry of the Wadati-Benioff zone under Chiapas and the distributions of the principal stresses along the subducted slab. Seismicity at the outer-rise region is not well located. A Poisson’s ratio of 0.24 was calculated for the crust of Chiapas. We located 321 earthquakes in the magnitude range from 3.3 to 5.6. Hypocenters define a Wadati-Benioff zone 39±4 km thick dipping 40° ± 3° to N45° E. Earthquake depths range from 10 km to 300 km. The Cocos plate dips nearly 25° in Oaxaca, 30° to 35° under the Gulf of Tehuantepec and 40° to the Southeast. A major change in dip occurs at the intersection of the Tehuantepec Ridge with the Middle America Trench. Seismicity in this zone is diffuse to depths of 200 km. Our data suggests a gradual increase of the dip of the Cocos plate from Oaxaca to Chiapas. Focal mechanisms of events with depths less than 50 km indicate that the subducted crust is under tension in this region, while at depths between 50 and 200 km there is a mixed pattern of stress distribution. At depths from 200 to 300 km the subducted lithosphere is under down-dip compression.La sismicidad registrada desde junio de 1994 a mayo de 1995, en una red portátil de estaciones sismológicas analógicas y digitales, definieron la geometría de la zona Wadati-Benioff bajo Chiapas, así como la distribución de los esfuerzos principales en la placa subducida. La sismicidad localizada en el antearco no fue bien localizada. Un módulo de Poisson de 0.24 fue calculado para la corteza de Chiapas. 321 sismos fueron localizados en el rango de magnitudes entre 3.3 y 5.6. Los hipocentros definieron la zona Wadati-Benioff de 39±4 km de grueso buzando 40°±3° hacia N45°E. La profundidad de los sismos varió entre 10 a 300 km. La placa de Cocos buza aproximadamente 25° en Oaxaca, 30° bajo el Golfo de Tehuantepec y 40° hacia el sudeste. Un fuerte cambio en el buzamiento de la placa de Cocos ocurre en la intersección de la cordillera de Tehuantepec y la Trinchera de Centro Amé- rica. La sismicidad en esta zona es difusa hasta profundidades de 200 km. Nuestros datos sugieren un incremento gradual del buzamiento de la placa de Cocos de Oaxaca a Chiapas. Los mecanismos focales de eventos con profundidades menores de 50 km indican que la placa subducida está bajo tensión, mientras que a profundidades entre 50 y 200 km la placa experimenta un régimen mixto de esfuerzos. A profundidades entre 200 y 300 km la litosfera subducida está bajo un régimen comprensivo en la dirección del buzamiento.Universidad Nacional Autónoma de México. Instituto de Geofísica1999-04-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttp://revistagi.geofisica.unam.mx/index.php/RGI/article/view/63510.22201/igeof.00167169p.1999.38.2.386Geofisica Internacional; Vol. 38 No. 2 (1999): April 1, 1999; 95-106Geofísica Internacional; Vol. 38 Núm. 2 (1999): Abril 1, 1999; 95-1062954-436X0016-716910.22201/igeof.00167169p.1999.38.2reponame:Geofísica Internacionalinstname:UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICOinstacron:UNAMspahttp://revistagi.geofisica.unam.mx/index.php/RGI/article/view/635/640https://creativecommons.org/licenses/by-nc-sa/4.0/info:eu-repo/semantics/openAccessoai:revistagi.geofisica.unam.mx:article/6352024-08-16T17:31:56Z |
| dc.title.none.fl_str_mv |
Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico |
| title |
Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico |
| spellingShingle |
Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico Rebollar, Cecilio J. Sismicidad zona de Wadati-Benioff mecanismos focales distribución de esfuerzos Seismicity Wadati-Benioff zone focal mechanisms stress distribution |
| title_short |
Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico |
| title_full |
Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico |
| title_fullStr |
Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico |
| title_full_unstemmed |
Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico |
| title_sort |
Distributions of stresses and geometry of the Wadati-Benioff zone under Chiapas, Mexico |
| dc.creator.none.fl_str_mv |
Rebollar, Cecilio J. Espíndola, Víctor H. Uribe, Antonio Mendoza, Antonio Pérez-Vertti, Arturo |
| author |
Rebollar, Cecilio J. |
| author_facet |
Rebollar, Cecilio J. Espíndola, Víctor H. Uribe, Antonio Mendoza, Antonio Pérez-Vertti, Arturo |
| author_role |
author |
| author2 |
Espíndola, Víctor H. Uribe, Antonio Mendoza, Antonio Pérez-Vertti, Arturo |
| author2_role |
author author author author |
| dc.subject.none.fl_str_mv |
Sismicidad zona de Wadati-Benioff mecanismos focales distribución de esfuerzos Seismicity Wadati-Benioff zone focal mechanisms stress distribution |
| topic |
Sismicidad zona de Wadati-Benioff mecanismos focales distribución de esfuerzos Seismicity Wadati-Benioff zone focal mechanisms stress distribution |
| description |
Seismicity recorded from June 1994 to May 1995 on a portable network of analog and digital seismic stations defines the geometry of the Wadati-Benioff zone under Chiapas and the distributions of the principal stresses along the subducted slab. Seismicity at the outer-rise region is not well located. A Poisson’s ratio of 0.24 was calculated for the crust of Chiapas. We located 321 earthquakes in the magnitude range from 3.3 to 5.6. Hypocenters define a Wadati-Benioff zone 39±4 km thick dipping 40° ± 3° to N45° E. Earthquake depths range from 10 km to 300 km. The Cocos plate dips nearly 25° in Oaxaca, 30° to 35° under the Gulf of Tehuantepec and 40° to the Southeast. A major change in dip occurs at the intersection of the Tehuantepec Ridge with the Middle America Trench. Seismicity in this zone is diffuse to depths of 200 km. Our data suggests a gradual increase of the dip of the Cocos plate from Oaxaca to Chiapas. Focal mechanisms of events with depths less than 50 km indicate that the subducted crust is under tension in this region, while at depths between 50 and 200 km there is a mixed pattern of stress distribution. At depths from 200 to 300 km the subducted lithosphere is under down-dip compression. |
| publishDate |
1999 |
| dc.date.none.fl_str_mv |
1999-04-01 |
| dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
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article |
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publishedVersion |
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http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/635 10.22201/igeof.00167169p.1999.38.2.386 |
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http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/635 |
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10.22201/igeof.00167169p.1999.38.2.386 |
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spa |
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spa |
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http://revistagi.geofisica.unam.mx/index.php/RGI/article/view/635/640 |
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https://creativecommons.org/licenses/by-nc-sa/4.0/ info:eu-repo/semantics/openAccess |
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https://creativecommons.org/licenses/by-nc-sa/4.0/ |
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openAccess |
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application/pdf |
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Universidad Nacional Autónoma de México. Instituto de Geofísica |
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Universidad Nacional Autónoma de México. Instituto de Geofísica |
| dc.source.none.fl_str_mv |
Geofisica Internacional; Vol. 38 No. 2 (1999): April 1, 1999; 95-106 Geofísica Internacional; Vol. 38 Núm. 2 (1999): Abril 1, 1999; 95-106 2954-436X 0016-7169 10.22201/igeof.00167169p.1999.38.2 reponame:Geofísica Internacional instname:UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO instacron:UNAM |
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UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO |
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UNAM |
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UNAM |
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Geofísica Internacional |
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Geofísica Internacional |
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