Differences in Attenuation of Ground Motion Perpendicular to the Mexican Subduction Zone between Colima and Guerrero: An Explanation Based on Numerical Modeling

ABSTRACT Ground-motion prediction models (GMPMs) are a critical tool in performing seismic hazard analyses; in turn, these studies condition structural designs. Consequently, new research has appeared not only with a regionalization focus but has also explored the prediction of intensities other than acceleration. We present a GMPM for peak ground velocity (PGV) and spectral velocity (Sv) for the Chilean subduction zone. Because of the limitations of VS30 as site proxy, the proposed model adds the site’s fundamental frequency (f0) as an explanatory variable for the site term in the GMPM. We developed the model for PGV and spectral response periods between 0.06 and 10 s. The total error (σ) of the model shows a slight reduction with the inclusion of the fundamental frequency (f0) compared with a similar model for the pseudoacceleration response spectrum in the same zone. We used the proposed model to predict structural damage during the 2010 Mw 8.8 Maule earthquake, showing a good fit with the geographical distribution of damage, and this creates an opportunity to characterize the seismic behavior of soil deposits, including basins, for urban planning.

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Relational database used for ground-motion model development in the NGA-sub project

Earthquake Spectra ◽

10.1177/87552930211055204 ◽

2021 ◽

pp. 875529302110552

Author(s):

Silvia Mazzoni ◽

Tadahiro Kishida ◽

Jonathan P Stewart ◽

Victor Contreras ◽

Robert B Darragh ◽

...

Keyword(s):

Subduction Zone ◽

Ground Motion ◽

Data Storage ◽

Relational Database ◽

Model Development ◽

Intensity Measures ◽

Motion Models ◽

Ground Motion Model ◽

Ground Motion Models ◽

Pseudo Spectral

The Next-Generation Attenuation for subduction zone regions project (NGA-Sub) has developed data resources and ground motion models for global subduction zone regions. Here we describe the NGA-Sub database. To optimize the efficiency of data storage, access, and updating, data resources for the NGA-Sub project are organized into a relational database consisting of 20 tables containing data, metadata, and computed quantities (e.g. intensity measures, distances). A database schema relates fields in tables to each other through a series of primary and foreign keys. Model developers and other users mostly interact with the data through a flatfile generated as a time-stamped output of the database. We describe the structure of the relational database, the ground motions compiled for the project, and the means by which the data can be accessed. The database contains 71,340 three-component records from 1880 earthquakes from seven global subduction zone regions: Alaska, Central America and Mexico, Cascadia, Japan, New Zealand, South America, and Taiwan. These data were processed on a component-specific basis to minimize noise effects in the data and remove baseline drifts. Provided ground motion intensity measures include peak acceleration, peak velocity, and 5%-damped pseudo-spectral accelerations for a range of oscillator periods.

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Spatiotemporal Variations in Slow Earthquakes Along the Mexican Subduction Zone

Journal of Geophysical Research Solid Earth ◽

10.1002/2017jb014690 ◽

2018 ◽

Vol 123 (2) ◽

pp. 1559-1575 ◽

Cited By ~ 5

Author(s):

J. Maury ◽

S. Ide ◽

V. M. Cruz-Atienza ◽

V. Kostoglodov

Keyword(s):

Subduction Zone ◽

Spatiotemporal Variations ◽

Slow Earthquakes ◽

Mexican Subduction Zone

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The influence of fluids in the unusually high-rate seismicity in the Ometepec segment of the Mexican subduction zone

Geophysical Journal International ◽

10.1093/gji/ggab106 ◽

2021 ◽

Cited By ~ 1

Author(s):

D Legrand ◽

A Iglesias ◽

S K Singh ◽

V Cruz-Atienza ◽

C Yoon ◽

...

Keyword(s):

Subduction Zone ◽

Temporal Distribution ◽

Aftershock Sequence ◽

High Rate ◽

Earth Tides ◽

P Value ◽

Plate Interface ◽

Flow Measurements ◽

Slow Slip Events ◽

Mexican Subduction Zone

Summary The rate of earthquakes with magnitudes Mw ≤ 7.5 in the Ometepec segment of the Mexican subduction zone is relatively high as compared to the neighboring regions of Oaxaca and Guerrero. Although the reason is not well understood, it has been reported that these earthquakes give rise to a large number of aftershocks. Our study of the aftershock sequence of the 2012 Mw7.4 Ometepec thrust earthquake suggests that it is most likely due to two dominant factors: (1) The presence of an anomalously high quantity of over-pressured fluids near the plate interface, and (2) the roughness of the plate interface. More than 5,400 aftershocks were manually detected during the first ten days following the 2012 earthquake. Locations were obtained for 2,419 events (with duration magnitudes Md ≥ 1.5). This is clearly an unusually high number of aftershocks for an earthquake of this magnitude. Furthermore, we generated a more complete catalog, using an unsupervised fingerprint technique, to detect more smaller events (15,593 within one month following the mainshock). For this catalog, a high b-value of 1.50 ± 0.10 suggests the presence of fluid release during the aftershock sequence. A low p-value (0.37 ± 0.12) of the Omori law reveals a slow decaying aftershock sequence. The temporal-distribution of aftershocks shows peaks of activity with two dominant periods of 12h and 24h that correlate with the Earth tides. To explain these observations, we suggest that the 2012 aftershock sequence is associated with the presence of over-pressured fluids and/or a heterogeneous and irregular plate interface related to the subduction of the neighboring seamounts. High fluid content has independently been inferred by magneto-telluric surveys and deduced from heat flow measurements in the region. The presence of fluids in the region has also been proposed to explain the occurrence of slow slip events, low frequency earthquakes, and tectonic tremors.

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