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Quintero, Ronnie; Güendel, Federico

doi:10.1023/a:1009867405248

Cited by 17 publications

(4 citation statements)

References 30 publications

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“…Microseismicity in central Costa Rica is mostly located in the vicinity of the subducting Cocos Plate and in the upper crust of the volcanic front (Protti et al 1994;Husen et al 2003;DeShon et al 2006). The upper crust near the Pacific coast of central Costa Rica shows less seismic activity (Protti et al 1995;Quintero & Güendel 2000). Recent seismicity and geodetic studies have found areas of the slab interface with increased seismicity (DeShon et al , 2006 and locked patches (Norabuena et al 2004;Ghosh et al 2008) that could rupture as a large earthquake.…”

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confidence: 99%

Seismic evidence for fluids in fault zones on top of the subducting Cocos Plate beneath Costa Rica

Avendonk

Holbrook

Lizarralde

et al. 2010

Geophysical Journal International

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S U M M A R YIn the 2005 TICOCAVA explosion seismology study in Costa Rica, we observed crustal turning waves with a dominant frequency of ∼10 Hz on a linear array of short-period seismometers from the Pacific Ocean to the Caribbean Sea. On one of the shot records, from Shot 21 in the backarc of the Cordillera Central, we also observed two seismic phases with an unusually high dominant frequency (∼20 Hz). These two phases were recorded in the forearc region of central Costa Rica and arrived ∼7 s apart and 30-40 s after the detonation of Shot 21. We considered the possibility that these secondary arrivals were produced by a local earthquake that may have happened during the active-source seismic experiment. Such high-frequency phases following Shot 21 were not recorded after Shots 22, 23 and 24, all in the backarc of Costa Rica, which might suggest that they were produced by some other source. However, earthquake dislocation models cannot produce seismic waves of such high frequency with significant amplitude. In addition, we would have expected to see more arrivals from such an earthquake on other seismic stations in central Costa Rica. We therefore investigate whether the high-frequency arrivals may be the result of a deep seismic reflection from the subducting Cocos Plate. The timing of these phases is consistent with a shear wave from Shot 21 that was reflected as a compressional (S×P) and a shear (S×S) wave at the top of the subducting Cocos slab between 35 and 55 km depth. The shift in dominant frequency from ∼10 Hz in the downgoing seismic wave to ∼20 Hz in the reflected waves requires a particular seismic structure at the interface between the subducting slab and the forearc mantle to produce a substantial increase in reflection coefficients with frequency. The spectral amplitude characteristics of the S×P and S×S phases from Shot 21 are consistent with a very high V p /V s ratio of 6 in ∼5 m thick, slab-parallel layers. This result suggests that a system of thin shear zones near the plate interface beneath the forearc is occupied by hydrous fluids under near-lithostatic conditions. The overpressured shear zone probably takes up fluids from the downgoing slab, and it may control the lower limit of the seismogenic zone.

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confidence: 99%

Seismic evidence for fluids in fault zones on top of the subducting Cocos Plate beneath Costa Rica

Avendonk

Holbrook

Lizarralde

et al. 2010

Geophysical Journal International

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“…Costa Rica is considered one of the countries with the greater seismicity of the region. Its complex tectonic framework, subduction zone and active volcanism in the continental zone, has motivated to develop more studies to reduce the seismic risk of the country (Protti and McNally 1994;Quintero and Güendel 2000;Moya-Fernández et al 2020). In seismic risk studies, three features must be taken into account: the hazard, vulnerability and damage value.…”

Section: Introductionmentioning

confidence: 99%

Seismic site classification of the Costa Rican Strong-Motion Network based on VS30 measurements and site fundamental period

et al. 2022

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In this paper, a new seismic site classification for the Costa Rican Strong-Motion Network (CRSMN) is proposed. The soil profile classification of the Costa Rican Seismic Code based on the average shear-wave velocity of the top 30 m (VS30) is used as a reference. The site fundamental period (Tf) is included as a parameter to complement the existing characterization. For this, the VS30 measurements from 52 accelerometric stations are related to the site fundamental period obtained through horizontal-to-vertical spectral ratios (HVSR) using ground motion records from the Costa Rican Strong-Motion Database. The H/V ratios are estimated with 5% damped acceleration response spectra and with traditional Fourier amplitude spectra from the S-wave window. From the relation between VS30 and Tf, different ranges of Tf are assigned to the existing soil profile classification and a graph with three-lines and four-areas is proposed to classify the stations of the CRSMN.

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“…As a result, many earthquakes occur along the subduction zone as well as active volcanism in the continental part. The outer slope side of the place generates normal faulting while reverse faulting takes place at depths between 15 and 50 km (Quintero and Güendel, 2000;DeShon et al, 2003;Norabuena et al, 2004). At depths between 50 and 280 km, intraplate or intra-slab earthquakes (deep subduction) occur and in general normal type mechanisms predominate (Guendel and Protti, 1998).…”

Section: Introductionmentioning

confidence: 99%

A Strong-Motion Database of Costa Rica: 20 Yr of Digital Records

Fernández

Ureña

Díaz

et al. 2020

Seismological Research Letters

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In this article, we present a strong-motion database from earthquakes recorded by the Earthquake Engineering Laboratory at the University of Costa Rica. The database consists of 2471 three-component accelerograms from 155 digitally recorded events. It covers the last 20 yr of measurements, including records from the 5 September 2012 Mw 7.6 Nicoya earthquake. The engineering and seismological communities can use this data either to conduct new research or to improve seismic hazard studies in the region. A catalog is also available with metadata of each record containing several intensity measures from the ground-motion time histories.

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Untitled

Cited by 17 publications

References 30 publications

Seismic evidence for fluids in fault zones on top of the subducting Cocos Plate beneath Costa Rica

Seismic evidence for fluids in fault zones on top of the subducting Cocos Plate beneath Costa Rica

Seismic site classification of the Costa Rican Strong-Motion Network based on VS30 measurements and site fundamental period

A Strong-Motion Database of Costa Rica: 20 Yr of Digital Records

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