The 2021 Mw 5.6 Earthquake in the Guyana Shield, South America: An Intraplate Event with No Reason to Occur
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F25%3A10508374" target="_blank" >RIV/00216208:11320/25:10508374 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=AXSGnO62Gz" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=AXSGnO62Gz</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1785/0320250002" target="_blank" >10.1785/0320250002</a>
Alternative languages
Result language
angličtina
Original language name
The 2021 Mw 5.6 Earthquake in the Guyana Shield, South America: An Intraplate Event with No Reason to Occur
Original language description
In 31 January 2021, an Mw 5.6 earthquake occurred in the Guyana shield, causing damage to adobe houses and ground cracks. A four-station network, installed in March, showed a shallow (1-3 km) southeast-northwest-oriented reverse fault, consistent with global and regional Centroid Moment Tensor (CMT) solutions. The rupture size (5 km long x 3 km wide) and 1 m slip (from Interferometric Synthetic Aperture Radar data) indicate a stress drop of 5-12 MPa, larger than the average in mid-plate South America. The large non-double-couple (DC) component of all CMT solutions is probably due to a complex rupture geometry, suggested by the aftershock distribution. None of the usual hypotheses to explain intraplate seismicity (weakness zones, stress concentration, and flexural stresses) is applicable to this event. There are no signs of crustal weakness zones: the major Paleoproterozoic faults trend southwest-northeast, orthogonal to the southeast-northwest rupture; the Mesozoic Takutu graben is 65 km away. None of the surface-wave tomographies indicate lithospheric thinning. Free-air anomalies near the epicenter have average values and do not indicate crustal loads increasing stresses locally. In the isolated epicentral area there is no mining activity nor hydroelectric reservoir to induce seismicity. No prior seismogenic feature was found to explain this activity.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10500 - Earth and related environmental sciences
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
The Seismic Record
ISSN
2694-4006
e-ISSN
2694-4006
Volume of the periodical
5
Issue of the periodical within the volume
2
Country of publishing house
US - UNITED STATES
Number of pages
11
Pages from-to
228-238
UT code for WoS article
001529871300001
EID of the result in the Scopus database
2-s2.0-105010061130