Imaging b -value depth variations within the Cocos and Rivera plates at the Mexican subduction zone

2018 ◽  
Vol 734-735 ◽  
pp. 33-43 ◽  
Author(s):  
Quetzalcoatl Rodríguez-Pérez ◽  
F. Ramón Zuñiga
Keyword(s):  
Subduction Zone ◽  
B Value ◽  
Mexican Subduction Zone

Seismic gaps and recurrence periods of large earthquakes along the Mexican subduction zone: A reexamination

1981 ◽  
Vol 71 (3) ◽  
pp. 827-843 ◽  
Author(s):  
S. K. Singh ◽  
L. Astiz ◽  
J. Havskov
Keyword(s):  
Subduction Zone ◽  
Risk Estimation ◽  
Source Parameters ◽  
Seismic Energy ◽  
B Value ◽  
Dislocation Model ◽  
Past Century ◽  
Seismic Gaps ◽  
Large Earthquakes ◽  
Mexican Subduction Zone

abstract Seismic gaps and recurrence periods of large, shallow interplate earthquakes along the Mexican subduction zone are reexamined after combining information from a catalog of nineteenth century's earthquakes, some relocated epicenters of the early part of this century, source parameters of recent large earthquakes, and redetermined magnitudes of great, shallow earthquakes of this century. Tehuantepec and Michoacan gaps have not experienced a large shock in this century and perhaps none in the past century; they are either aseismic or have anomalously large repeat times. Guerrero, Jalisco, and Ometepec regions presently appear to have a high seismic potential. Observed average repeat times of large earthquakes (Ms ≳ 7.4) in six regions (east, central, and west Oaxaca, San Marcos, Petatlan, and Colima) are between 32 to 56 yr. Data of this century indicate that the strain is released mostly in large events (Ms ≳ 7.4). A simple dislocation model with parameters obtained from the studies of recent earthquakes explains the observed recurrence periods quite well. The b value for this zone is not meaningful, an observation which is of significance for seismic risk estimation. Most of seismic moment (or, equivalently, seismic energy) release since 1800 appears to occur for 15 yr followed by relative quiescence in the next 15 yr.

scholarly journals Gutenberg-Richter b value studies along the Mexican Subduction Zone and data constraints

2020 ◽  
Vol 59 (4) ◽  
pp. 285-298
Author(s):  
Lenin Ávila-Barrientos ◽  
F. Alejandro Nava Pichardo
Keyword(s):  
Seismic Hazard ◽  
Subduction Zone ◽  
B Value ◽  
Seismicity Rates ◽  
Magnitude Scales ◽  
Data Constraints ◽  
Large Earthquakes ◽  
Adequate Data ◽  
Seismic Catalog ◽  
Mexican Subduction Zone

The Gutenberg-Richter b value is one of the most important tools for seismic hazard studies; this value is most useful in estimating seismicity rates, and also is related to ambient stress levels and shows changes precursory to the occurrence of large earthquakes. However, correct and reliable determinations of the b value are critically dependent on having adequate data samples. Studies oriented to corroborate whether precursory changes in the b value occur before large (M ? 7.0) along the Mexican subduction zone, were done based on data from the Servicio Sismológico Nacional (SSN, Mexico’s National Seismological Service) seismic catalog, from 1988 to 2018. Results for five earthquakes are suggestive that precursory changes may occur, but differences between measured values are not significant because of large uncertainties due to the SSN using different magnitude scales for small (below M ~4.5) and medium to large (above M ~4.5) magnitudes. We submit that until an appropriate scale is implemented for small magnitudes, results from b-value studies based on SSN data should be considered critically.

Spatiotemporal Variations in Slow Earthquakes Along the Mexican Subduction Zone

2018 ◽  
Vol 123 (2) ◽  
pp. 1559-1575 ◽  
Author(s):  
J. Maury ◽  
S. Ide ◽  
V. M. Cruz-Atienza ◽  
V. Kostoglodov
Keyword(s):  
Subduction Zone ◽  
Spatiotemporal Variations ◽  
Slow Earthquakes ◽  
Mexican Subduction Zone

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

2021 ◽  
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.

Systematic characterization of slow slip events along the Mexican subduction zone from 2000 to 2019

2020 ◽  
Author(s):  
Mathilde Radiguet ◽  
Ekaterina Kazachkina ◽  
Louise Maubant ◽  
Nathalie Cotte ◽  
Vladimir Kostoglodov ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Subduction Zones ◽  
Scaling Laws ◽  
Temporal Evolution ◽  
Seismic Gap ◽  
Slow Slip ◽  
Slow Slip Events ◽  
Grace Data ◽  
Spatio Temporal ◽  
Mexican Subduction Zone

<p>Slow slip events (SSEs) represent a significant mechanism of strain release along several subduction zones, and understanding their occurrence and relations with major earthquake asperities is essential for a comprehensive understanding of the seismic cycle. Here, we focus on the Mexican subduction zone, characterized by the occurrence of recurrent large slow slip events (SSEs), both in the Guerrero region, where the SSEs are among the largest observed worldwide, and in the Oaxaca region, where smaller, more frequent SSEs occur. Up to now, most slow slip studies in the Mexican subduction zone focused either on the detailed analysis of a single event, were limited to a small area (Guerrero or Oaxaca), or were limited to data before 2012 [e.g.1-4]. In this study, our aim is to build an updated and consistent catalog of major slow slip events in the Guerrero-Oaxaca region.</p><p>We use an approach similar to Michel et al. 2018 [5]. We analyze the GPS time series from 2000 to 2019 using Independent Component Analysis (ICA), in order to separate temporally varying sources of different origins (seasonal signals, SSEs and afterslip of major earthquakes). We are able to isolate a component corresponding to seasonal loading, which matches the temporal evolution of displacement modeled from the GRACE data. The sources (independent components) identified as tectonic sources of deep origin are inverted for slip on the subduction interface. We thus obtain a model of the spatio-temporal evolution of aseismic slip on the subduction interface over 19 years, from which we can isolate around 30 individual slow slip events of M<sub>w </sub>> 6.2.</p><p> The obtained catalog is coherent with previous studies (in terms of number of events detected, magnitude and duration) which validates the methodology. The observed moment-duration scaling is close to M<sub>0</sub>~T<sup>3 </sup>as recently suggested by Michel [6] for Cascadia SSEs, and our study extends the range of magnitude considered in their analysis. Finally, we also investigate the spatio-temporal relations between the SSEs occurring in the adjacent regions of Guerrero and Oaxaca, and their interaction with local and distant earthquakes.</p><p> </p><p>References:</p><ol><li>Kostoglodov, V. et al. A large silent earthquake in the Guerrero seismic gap, Mexico. Geophys. Res. Lett <strong>30</strong>, 1807 (2003).</li> <li>Graham, S. et al. Slow Slip History for the Mexico Subduction Zone: 2005 Through 2011. Pure and Applied Geophysics 1–21 (2015). doi:10.1007/s00024-015-1211-x</li> <li>Larson, K. M., Kostoglodov, V. & Shin’ichi Miyazaki, J. A. S. The 2006 aseismic slow slip event in Guerrero, Mexico: New results from GPS. Geophys. Res. Lett. <strong>34</strong>, L13309 (2007).</li> <li>Radiguet, M. et al. Slow slip events and strain accumulation in the Guerrero gap, Mexico. J. Geophys. Res. <strong>117</strong>, B04305 (2012).</li> <li>Michel, S., Gualandi, A. & Avouac, J.-P. Interseismic Coupling and Slow Slip Events on the Cascadia Megathrust. Pure Appl. Geophys. (2018). doi:10.1007/s00024-018-1991-x</li> <li>Michel, S., Gualandi, A. & Avouac, J. Similar scaling laws for earthquakes and Cascadia slow-slip events. Nature <strong>574, </strong>522–526 (2019) doi:10.1038/s41586-019-1673-6</li> </ol><p> </p>

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