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Titolo:
Viscoelastic shear zone model of a strike-slip earthquake cycle
Autore:
Pollitz, FF;
Indirizzi:
Univ Calif Davis, Dept Geol, Davis, CA USA Univ Calif Davis Davis CA USAUniv Calif Davis, Dept Geol, Davis, CA USA
Titolo Testata:
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
fascicolo: B11, volume: 106, anno: 2001,
pagine: 26541 - 26560
SICI:
0148-0227(20011110)106:B11<26541:VSZMOA>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
SAN-ANDREAS FAULT; 1992 LANDERS EARTHQUAKE; SOUTHERN-CALIFORNIA; EASTERN CALIFORNIA; CRUSTAL DEFORMATION; FOCAL MECHANISMS; COUPLING MODEL; MOJAVE-DESERT; BIG BEND; MOTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Pollitz, FF US Geol Survey, MS 977,345 Middlefield Rd, Menlo Pk, CA 94025 USA US Geol Survey MS 977,345 Middlefield Rd Menlo Pk CA USA 94025
Citazione:
F.F. Pollitz, "Viscoelastic shear zone model of a strike-slip earthquake cycle", J GEO R-SOL, 106(B11), 2001, pp. 26541-26560

Abstract

I examine the behavior of a two-dimensional (2-D) strike-slip fault systemembedded in a I-D elastic layer (schizosphere) overlying a uniform viscoelastic half-space (plastosphere) and within the boundaries of a finite widthshear zone. The viscoelastic coupling model of Savage and Prescott [1978] considers the viscoelastic response of this system, in the absence of the shear zone boundaries, to an earthquake occurring within the upper elastic layer, steady slip beneath a prescribed depth, and the superposition of the responses of multiple earthquakes with characteristic slip occurring at regular intervals. So formulated, the viscoelastic coupling model predicts that sufficiently long after initiation of the system, (1) average fault-parallel velocity at any point is the average slip rate of that side of the fault and (2) far-field velocities equal the same constant rate. Because of thesensitivity to the mechanical properties of the schizosphere-plastosphere system (i.e., elastic layer thickness, plastosphere viscosity), this model has been used to infer such properties from measurements of interseismic velocity. Such inferences exploit the predicted behavior at a known time within the earthquake cycle. By modifying the viscoelastic coupling model to satisfy the additional constraint that the absolute velocity at prescribed shear zone boundaries is constant, I find that even though the time-averaged behavior remains the same, the spatiotemporal pattern of surface deformation (particularly its temporal variation within an earthquake cycle) is markedly different from that predicted by the conventional viscoelastic couplingmodel. These differences are magnified as plastosphere viscosity is reduced or as the recurrence interval of periodic earthquakes is lengthened. Application to the interseismic velocity field along the Mojave section of the San Andreas fault suggests that the region behaves mechanically like a similar to 600-km-wide shear zone accommodating 50 mm/yr fault-parallel motion distributed between the San Andreas fault system and Eastern California Shear Zone.

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Documento generato il 20/01/20 alle ore 10:31:34