The seismic source parameters of the 1991 Costa Rica aftershock sequence: evidence for a transcurrent plate boundary

Fan Guangwei Fan, Susan Beck, T. C. Wallace

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The April 22, 1991, Valle de la Estrella, Costa Rica earthquake (Ms = 7.6) was a back-arc thrusting event associated with the underthrusting of the Caribbean plate beneath Central America. A network of three PASSCAL-type, portable instruments was deployed to monitor the aftershock activity in southern Costa Rica 2 to 6 weeks after the main shock. The focal mechanisms are generally in good agreement with P wave first-motion fault plane solutions determined from a local short-period network. The aftershocks show a clear spatial segmentation based on focal mechanism type. Most aftershocks near or southeast of the main shock were thrusting events with focal mechanisms similar to the main shock. In contrast, a cluster of aftershocks northwest of the main shock showed dominantly left-lateral, strike-slip motion on a northeasterly striking nodal plane. -from Authors

Original languageEnglish (US)
JournalJournal of Geophysical Research: Space Physics
Volume98
Issue numberB9
StatePublished - 1993

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Costa Rica
source parameters
seismic source
plate boundary
aftershock
Earthquakes
focal mechanism
shock
Central America
Caribbean plate
fault plane
P waves
segmentation
P-wave
slip
earthquakes
arcs
earthquake

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)
  • Environmental Science(all)

Cite this

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abstract = "The April 22, 1991, Valle de la Estrella, Costa Rica earthquake (Ms = 7.6) was a back-arc thrusting event associated with the underthrusting of the Caribbean plate beneath Central America. A network of three PASSCAL-type, portable instruments was deployed to monitor the aftershock activity in southern Costa Rica 2 to 6 weeks after the main shock. The focal mechanisms are generally in good agreement with P wave first-motion fault plane solutions determined from a local short-period network. The aftershocks show a clear spatial segmentation based on focal mechanism type. Most aftershocks near or southeast of the main shock were thrusting events with focal mechanisms similar to the main shock. In contrast, a cluster of aftershocks northwest of the main shock showed dominantly left-lateral, strike-slip motion on a northeasterly striking nodal plane. -from Authors",
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AU - Guangwei Fan, Fan

AU - Beck, Susan

AU - Wallace, T. C.

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AB - The April 22, 1991, Valle de la Estrella, Costa Rica earthquake (Ms = 7.6) was a back-arc thrusting event associated with the underthrusting of the Caribbean plate beneath Central America. A network of three PASSCAL-type, portable instruments was deployed to monitor the aftershock activity in southern Costa Rica 2 to 6 weeks after the main shock. The focal mechanisms are generally in good agreement with P wave first-motion fault plane solutions determined from a local short-period network. The aftershocks show a clear spatial segmentation based on focal mechanism type. Most aftershocks near or southeast of the main shock were thrusting events with focal mechanisms similar to the main shock. In contrast, a cluster of aftershocks northwest of the main shock showed dominantly left-lateral, strike-slip motion on a northeasterly striking nodal plane. -from Authors

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