Chapter 9 Source properties of volcano-tectonic earthquakes
2003; Elsevier BV; Linguagem: Inglês
10.1016/s1871-644x(03)80209-7
ISSN2212-2028
Tópico(s)Seismology and Earthquake Studies
ResumoPublisher SummaryThis chapter discusses a group of volcano-tectonic earthquakes that includes the earthquakes generated by stress, which arise during magma migration in the earth's crust. They correspond to A- and B-type events of Minakami's classifications or to high-, mix-, and low-frequency earthquakes of McNutt's classification. These earthquakes may be caused by a shear failure, a tensile failure, or fluid pressurization processes and may occur during the magma movement from the depth to the earth's surface through conduits and dikes, thereby producing the rupture at the tip of magma body and at adjacent fault systems. The focal mechanisms and spectral properties of these earthquakes are also discussed in the chapter. Seismological practice and theoretical studies show a double-couple source for shear faulting that produces volcano-tectonic earthquakes. This model predicts the quadrant distribution of P-wave first motions using stereographic projection and allows the discrimination of the three main types of faulting in earthquake foci: strike-slip, thrust, and normal fault.
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