TY - JOUR
T1 - Inter-plate coupling in the Nicoya Peninsula, Costa Rica, as deduced from a trans-peninsula GPS experiment
AU - Iinuma, Takeshi
AU - Protti, Marino
AU - Obana, Koichiro
AU - González, Victor
AU - Van der Laat, Rodolfo
AU - Kato, Teruyuki
AU - Miyazaki, Shin'ichi
AU - Kaneda, Yoshiyuki
AU - Hernández, Enrique
N1 - Funding Information:
We would like to thank Dr. Roland Bürgmann and Dr. Paul Lundgren for their critical reviews of the manuscript. This research was funded by the Japan International Cooperation Agency (JICA) and by the Nicoya Seismic Gap Monitoring Project at OVSICORI. Figures were made using GMT [15] . For this study, we have used the computer systems at the Earthquake Information Center of Earthquake Research Institute, the University of Tokyo. [RV]
PY - 2004/6/30
Y1 - 2004/6/30
N2 - We investigated the state of plate coupling at the subduction zone beneath the Nicoya Peninsula, northwestern Costa Rica, from 1.5 years of trans-peninsula GPS campaign experiments. This area is recognized as a seismic gap located between the rupture areas of two M≥7 earthquakes that occurred in the early 1990s, and it has not ruptured since 1950. We carried out campaign GPS observations beginning in autumn 2001 to obtain the profile of site velocities across the peninsula for the interseismic period. The obtained velocity field indicates a strong coupling at the plate interface. However, velocity directions deflect counterclockwise, which suggests a trench-parallel forearc sliver motion of Nicoya Peninsula at ∼8.5 mm/year. An inversion analysis to infer inter-plate coupling at Nicoya seismic gap shows that the strongly coupled zone agrees well with seismogenic zone inferred from seismicity. Cumulative slip deficits since 1950 at the Nicoya seismic gap would produce a thrust earthquake as large as MW≥7.5.
AB - We investigated the state of plate coupling at the subduction zone beneath the Nicoya Peninsula, northwestern Costa Rica, from 1.5 years of trans-peninsula GPS campaign experiments. This area is recognized as a seismic gap located between the rupture areas of two M≥7 earthquakes that occurred in the early 1990s, and it has not ruptured since 1950. We carried out campaign GPS observations beginning in autumn 2001 to obtain the profile of site velocities across the peninsula for the interseismic period. The obtained velocity field indicates a strong coupling at the plate interface. However, velocity directions deflect counterclockwise, which suggests a trench-parallel forearc sliver motion of Nicoya Peninsula at ∼8.5 mm/year. An inversion analysis to infer inter-plate coupling at Nicoya seismic gap shows that the strongly coupled zone agrees well with seismogenic zone inferred from seismicity. Cumulative slip deficits since 1950 at the Nicoya seismic gap would produce a thrust earthquake as large as MW≥7.5.
KW - Costa Rica
KW - Forearc sliver
KW - Inter-plate coupling
KW - Nicoya Seismic Gap
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U2 - 10.1016/j.epsl.2004.04.016
DO - 10.1016/j.epsl.2004.04.016
M3 - Article
AN - SCOPUS:2942654848
VL - 223
SP - 203
EP - 212
JO - Earth and Planetary Sciences Letters
JF - Earth and Planetary Sciences Letters
SN - 0012-821X
IS - 1-2
ER -