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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Earthquake source properties of a shallow induced seismic sequence in SE Brazil

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Agurto-Detzel, Hans ; Bianchi, Marcelo ; Prieto, German A. ; Assumpcao, Marcelo
Total Authors: 4
Document type: Journal article
Source: JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH; v. 122, n. 4, p. 2784-2797, APR 2017.
Web of Science Citations: 2

We study source parameters of a cluster of 21 very shallow (< 1 km depth) small-magnitude (M-w< 2) earthquakes induced by percolation of water by gravity in SE Brazil. Using a multiple empirical Green's functions (meGf) approach, we estimate seismic moments, corner frequencies, and static stress drops of these events by inversion of their spectral ratios. For the studied magnitude range (-0.3< M-w< 1.9), we found an increase of stress drop with seismic moment. We assess associated uncertainties by considering different signal time windows and by performing a jackknife resampling of the spectral ratios. We also calculate seismic moments by full waveform inversion to independently validate our moments from spectral analysis. We propose repeated rupture on a fault patch at shallow depth, following continuous inflow of water, as the cause for the observed low absolute stress drop values (< 1 MPa) and earthquake size dependency. To our knowledge, no other study on earthquake source properties of shallow events induced by water injection with no added pressure is available in the literature. Our study suggests that source parameter characterization may provide additional information of induced seismicity by hydraulic stimulation. (AU)

FAPESP's process: 14/26330-0 - Source characterization of induced seismicity in Bebedouro, Brazil, and deep earthquakes in South America
Grantee:Hans Alex Agurto Detzel
Support type: Scholarships abroad - Research Internship - Post-doctor
FAPESP's process: 14/09455-3 - Induced earthquakes in Bebedouro, SE Brazil: seismicity, velocity structure and focal mechanisms
Grantee:Hans Alex Agurto Detzel
Support type: Scholarships in Brazil - Post-Doctorate