Spatial variations of b-values in the subduction zone of Central America
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| Format: | Artículo científico |
| Language: | en |
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Universidad Nacional Autónoma de México
2003
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| author | David A. Monterroso |
| author_facet | David A. Monterroso |
| contents | Spatial variations of b-values in the subduction zone of Central America David A. Monterroso Ota Kulhánek Ciencias de la Tierra value stress volcanic chain subduction zone Central America Frequency-magnitude distribution along the Mid-American Trench (MAT) has been studied by means of 2345 earthquakesduring the period 1964-1994. We used the regional MIDAS catalogue with a magnitude of completeness of 4.2. To resolve the bvalueas a function of depth (one dimensional approach), we applied vertically sliding windows containing a constant number ofevents. To obtain more details in the b distribution, we projected catalogue hypocenters in three selected regions (approximatelyGuatemala and El Salvador, Nicaragua, Costa Rica), onto planes perpendicular to the trench. The b-values were calculated insliding cylindrical volumes (two-dimensional approach) containing a constant number of earthquakes and centered at nodes of a5 km x 5 km grid. The b-value varies significantly along a large part of MAT. High b-values were identified in the upper part of theslab at depths of 80-110 km beneath Guatemala-El Salvador and at depths 130-170 km beneath Nicaragua. Anomalous (high) bvaluesin the lower part of the slab were located at depths of 50-90 km and 50-160 km beneath Guatemala-El Salvador andNicaragua, respectively. Anomalies observed at the upper part of the slab may be related to dehydration and successive increase inpore pressure in the down-going lithosphere, which may generate volcanism above the anomalies in the upper part of the slab.Anomalies on the lower surface of the Wadati-Benioff zone are likely to be associated with high thermal gradients between theslab and mantle. 2003 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56842401 en http://www.redalyc.org/revista.oa?id=568 Geofísica Internacional application/pdf Universidad Nacional Autónoma de México Geofísica Internacional (México) Num.4 Vol.42 |
| format | Artículo científico |
| id | redalyc_56842401 |
| institution | Redalyc |
| language | en |
| publishDate | 2003 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | Spatial variations of b-values in the subduction zone of Central America David A. Monterroso Ciencias de la Tierra value stress volcanic chain subduction zone Central America Spatial variations of b-values in the subduction zone of Central America David A. Monterroso Ota Kulhánek Ciencias de la Tierra value stress volcanic chain subduction zone Central America Frequency-magnitude distribution along the Mid-American Trench (MAT) has been studied by means of 2345 earthquakesduring the period 1964-1994. We used the regional MIDAS catalogue with a magnitude of completeness of 4.2. To resolve the bvalueas a function of depth (one dimensional approach), we applied vertically sliding windows containing a constant number ofevents. To obtain more details in the b distribution, we projected catalogue hypocenters in three selected regions (approximatelyGuatemala and El Salvador, Nicaragua, Costa Rica), onto planes perpendicular to the trench. The b-values were calculated insliding cylindrical volumes (two-dimensional approach) containing a constant number of earthquakes and centered at nodes of a5 km x 5 km grid. The b-value varies significantly along a large part of MAT. High b-values were identified in the upper part of theslab at depths of 80-110 km beneath Guatemala-El Salvador and at depths 130-170 km beneath Nicaragua. Anomalous (high) bvaluesin the lower part of the slab were located at depths of 50-90 km and 50-160 km beneath Guatemala-El Salvador andNicaragua, respectively. Anomalies observed at the upper part of the slab may be related to dehydration and successive increase inpore pressure in the down-going lithosphere, which may generate volcanism above the anomalies in the upper part of the slab.Anomalies on the lower surface of the Wadati-Benioff zone are likely to be associated with high thermal gradients between theslab and mantle. 2003 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56842401 en http://www.redalyc.org/revista.oa?id=568 Geofísica Internacional application/pdf Universidad Nacional Autónoma de México Geofísica Internacional (México) Num.4 Vol.42 |
| title | Spatial variations of b-values in the subduction zone of Central America |
| topic | Ciencias de la Tierra value stress volcanic chain subduction zone Central America |
| url | https://www.redalyc.org/articulo.oa?id=56842401 |