Seismic energy radiated by earthquakes in the Basin and Range Province of Sonora, Mexico, near the rupture of the 1887 M
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ORIGINAL ARTICLE
Seismic energy radiated by earthquakes in the Basin and Range Province of Sonora, Mexico, near the rupture of the 1887 Mw 7.5 earthquake Raúl R. Castro
&
Gina P. Villalobos-Escobar
Received: 22 May 2020 / Accepted: 24 August 2020 # Springer Nature B.V. 2020
Abstract We estimated the seismic energy radiated by 47 earthquakes located near the faults that rupture during the 3 May 1887 Mw 7.5 Sonora earthquake in the Mexican Basin and Range Province. We retrieve source parameters from seismograms recorded by the local network RESNES (Red Sismica del Noreste de Sonora) that operated from 2003 to 2011, using a spectral inversion technique. We calculated the seismic energy by integrating the square velocity source spectrum of the earthquakes analyzed. We found that events with highscaled seismic energy (Es/Mo) are located at the southern end of the fault that rupture in 1887, between the stepovers of the fault segments Teras and Otates. It is likely that tectonic stress accumulated in that zone after Article Highlights • Events with the higher scaled seismic energy (Es/Mo) are located at the southern end of the 1887 fault rupture, between the stepovers of the Teras and Otates fault segments. • The estimates of ES/Mo are consistent with the elastic impact model (Tsai and Hirth, 2020) that predicts that earthquakes of different sizes can have the same high-frequency spectral shape when they generate in fault zones having similar elastic properties. • We estimate an average log(Es/Mo) = − 5.76 and found that most earthquakes analyzed have low apparent stress. R. R. Castro (*) Departamento de Sismología, División Ciencias de la Tierra, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), 22860 Ensenada, Baja California, Mexico e-mail: [email protected] G. P. Villalobos-Escobar Facultad de Ingeniería “Arturo Narro Siller”, Universidad Autónoma de Tamaulipas, Tampico, Mexico
the fault ruptured. We estimate an average log(Es/Mo) = − 5.76 and found that most earthquakes analyzed have low apparent stress, varying between 0.5 × 10−3 and 1.85 MPa, with an average value of 0.0521 MPa. The apparent stress is heterogeneous not showing a clear correlation with seismic moment or focal depth. Keywords Seismic energy . Basin and Range . Sonora . Mexico
1 Introduction The seismic energy radiated by an earthquake is useful to evaluate source parameters like the size of the event and to study the dynamics of the rupture process. In addition, the distribution of seismic energy released can be used to identify regions where tectonic stress has been accumulating. The northeastern Sonora, Mexico region is part of the Basin and Range Province, where normal faults and half-grabens are characteristic of this region. The seismotectonics of this region has been extensively studied by Suter (2006, 2008a, b), Suter and Contreras (2002), and more recently by Castro et al. (2010) and Castro (2015). A local seismic network, RESNES (Red Sismica del Noreste de Sonora), was installed in 2002 by CICESE (Centro d
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