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Persistent tremor within the northern Costa Rica seismogenic zone
Author(s) -
Walter Jacob I.,
Schwartz Susan Y.,
Protti J. Marino,
Gonzalez Victor
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl045586
Subject(s) - episodic tremor and slip , slipping , geology , slip (aerodynamics) , seismology , subduction , geodetic datum , geodesy , tectonics , geometry , physics , mathematics , thermodynamics
We identify tremor using a spectral detection method and characterize its occurrence over a period of four years (2006–2009) in the vicinity of the Nicoya Peninsula, Costa Rica. Although a few major tremor events accompanied by geodetic slow slip occur, much of the tremor record consists of minor episodes with short duration and no detectable geodetic slip. Its persistent occurrence suggests that some portion of the interface is experiencing slow slip nearly continuously driving small patches to fail in accelerated slip. Locations indicate that much of the tremor occurs at shallow depth, in freely slipping regions of the seismogenic zone. This result is significant in that locations of slow slip and tremor at other subduction zones are largely limited to the downdip frictional transition. Tremor locations may help to refine the heterogeneous distribution of locked and freely slipping patches within the Costa Rica seismogenic zone.