HR: 0800h
AN: S51A-03    [Abstracts]
TI: Seismicity of the Subducted Caribbean Plate in Panama
AU: * Camacho, E
EM: ecamacho@cableonda.net
AF: Instituto de Geociencias, Universidad de Panama, Panama City, Panama, Panama
AU: Pacheco, J F
EM: javier@ollin.igeofcu.unam.mx
AF: Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico, DF 04510, Mexico
AU: Hutton, W
EM: whutton@southtexascollege.edu
AF: South Texas College, P.O. Box 9701, McAllen, TX 78502-9701, United States
AB: The Panama microplate is bounded by convergent boundaries to the north (North Panama deformed belt; NPDB) and south (South Panama deformed belt; SPDB and Middle American Trench; MAT), suturing with South America along the Atrato valley to the east and the Central Costa Rica deformed belt (CCRDB) to the west. GPS measured convergence rates between the NPDB and the Caribbean plate are to the southwest at 7 mm/a. Seismicity of the portion of the NPDB along the isthmus of Panama is poorly understood, even though the largest recorded earthquake in Panama (7 September, 1882 (M7.9)) occurred on this boundary. This earthquake caused extensive damage in central Panama and produced a tsunami that killed 75 people in Comarca de San Blas. A preliminary study of seismicity in the area, using high quality seismic data recorded by local stations between 1996-2006, suggests that most events were of intermediate depth (40-70km) with a geometry indicative of a subducted plate. We also note that focal mechanisms show a complex stress field in this area possibly due to activation of pre-existing faults and internal deformation of the Caribbean plate being subducted. The existence of a well-defined Wadati-Bennioff zone below northern Panama should be included in future risk assessment evaluations.
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2007 Joint Assembly