The 2017 M_W 8.2 Chiapas, Mexico Earthquake: Energetic Slab Detachment
Abstract
On 8 September 2017, a great (M_w 8.2) normal faulting earthquake ruptured within the subducting Cocos Plate ~70 km landward from the Middle American Trench beneath the Tehuantepec gap. Iterative inversion and modeling of teleseismic and tsunami data and prediction of GPS displacements indicate that the steeply dipping rupture extended ~180 km to the northwest along strike toward the Oaxaca coast and from ~30 to 70 km in depth, with peak slip of ~13 m. The rupture likely broke through the entire lithosphere of the young subducted slab in response to downdip slab pull. The plate boundary region between the trench and the fault intersection with the megathrust appears to be frictionally coupled, influencing location of the detachment. Comparisons of the broadband body wave magnitude (m_B) and moment-scaled radiated energy (E_R/M_0) establish that intraslab earthquakes tend to be more energetic than interplate events, accounting for strong ground shaking observed for the 2017 event.
Additional Information
© 2017 American Geophysical Union. Received 19 OCT 2017; Accepted 22 NOV 2017; Accepted article online 4 DEC 2017; Published online 11 DEC 2017. The IRIS DMS data center (http://www.iris.edu/hq/) was used to access the seismic data from Global Seismic Network and Federation of Digital Seismic Network stations. GPS data at stations TNCY, TNNP, TNSJ, OXUM, CN25, and MTP1 are provided by Tom Herring through UNAVCO webpage (https://www.unavco.org). Data for OXPE, OXTH, ICHS, and TNPJ are determined from rapid time series from Nevada Geodetic Laboratory (http://geodesy.unr.edu). Tsunami waveform data were obtained from the NOAA National Data Buoy Center (http://www.ndbc.noaa.gov/). We thank Rob Clayton for sharing broadband data from the Mexican National Seismic Network (MX). We thank S. K. Singh for sharing his papers on normal faulting beneath Mexico. We thank X. Pérez-Campos and J. C. Castellanos for discussion about SSN aftershock locations. This work was benefitted from discussions at Seismo Lab coffee hour at Caltech. We thank G. Hayes, an anomalous reviewer, and the Editor A. V. Newman for their constructive reviews. K. D. Koper kindly provided his backprojection software. This work was supported by National Natural Science Foundation of China grants U170160005 and 41372198 to Lingling Ye and National Science Foundation grant EAR1245717 to Thorne Lay.Attached Files
Published - Ye_et_al-2017-Geophysical_Research_Letters.pdf
Supplemental Material - grl56727-sup-0001-2017GL076085_S01.docx
Supplemental Material - grl56727-sup-0002-2017GL076085_S01.mp4
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Additional details
- Eprint ID
- 83681
- Resolver ID
- CaltechAUTHORS:20171205-065841607
- U170160005
- National Natural Science Foundation of China
- 41372198
- National Natural Science Foundation of China
- EAR-1245717
- NSF
- Created
-
2017-12-12Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory, Division of Geological and Planetary Sciences