Evaluation of static stress on a fault plane from a Green's function

1974 ◽  
Vol 64 (6) ◽  
pp. 1629-1633
Author(s):  
D. J. Andrews
Keyword(s):  
Shear Strain ◽  
Green's Function ◽  
Plane Stress ◽  
Representation Theorem ◽  
Stress Drop ◽  
Numerical Evaluation ◽  
Analytic Solution ◽  
Fault Plane ◽  
Static Stress ◽  
Field Point

abstract Direct numerical evaluation of shear strain on a fault plane using the representation theorem is not possible because source points near the field point give large and canceling contributions to the integral. The representation theorem for strain can be integrated by parts to obtain an expression valid everywhere and suitable for numerical evaluation on the fault plane. Stress-drop evaluated by this method for the circular dislocation of Keylis-Borok agrees well with the analytic solution.

Source dimensions and stress drops of small earthquakes near Parkfield, California

1984 ◽  
Vol 74 (1) ◽  
pp. 27-40
Author(s):  
M. E. O'Neill
Keyword(s):  
Stress Drop ◽  
Small Region ◽  
Static Stress ◽  
Depth Range ◽  
Zero Crossing ◽  
Source Dimensions ◽  
Duration Magnitude ◽  
Short Period ◽  
Static Stress Drop ◽  
Stress Drops

Abstract Source dimensions and stress drops of 30 small Parkfield, California, earthquakes with coda duration magnitudes between 1.2 and 3.9 have been estimated from measurements on short-period velocity-transducer seismograms. Times from the initial onset to the first zero crossing, corrected for attenuation and instrument response, have been interpreted in terms of a circular source model in which rupture expands radially outward from a point until it stops abruptly at radius a. For each earthquake, duration magnitude MD gave an estimate of seismic moment MO and MO and a together gave an estimate of static stress drop. All 30 earthquakes are located on a 6-km-long segment of the San Andreas fault at a depth range of about 8 to 13 km. Source radius systemically increases with magnitude from about 70 m for events near MD 1.4 to about 600 m for an event of MD 3.9. Static stress drop ranges from about 2 to 30 bars and is not strongly correlated with magnitude. Static stress drop does appear to be spatially dependent; the earthquakes with stress drops greater than 20 bars are concentrated in a small region close to the hypocenter of the magnitude 512 1966 Parkfield earthquake.

Stress in an elastic hump: the effects of glacier flow over elastic bedrock

1975 ◽  
Vol 344 (1637) ◽  
pp. 157-173 ◽  
Keyword(s):  
Plane Stress ◽  
Complex Variable ◽  
Analytic Solution ◽  
Rational Functions ◽  
Fortran Program ◽  
Stress Fields ◽  
Infinite Domain ◽  
Principal Directions ◽  
Glacier Flow ◽  
Principal Strains

Stress fields in an isotropic elastic semi-infinite domain with a humped contour subjected to applied tractions are obtained for plane strain or plane stress conditions. Domains mapped conformally onto the half-plane by a class of rational functions are considered and a complex variable method is used to determine an analytic solution. A general Fortran program has been constructed to determine stresses, principal directions, principal strains, and maximum shear tractions at specified points.

scholarly journals Ice Stream C, Antarctica, sticky spots detected by microearthquake monitoring

1994 ◽  
Vol 20 ◽  
pp. 183-186 ◽  
Author(s):  
S. Anandakrishnan ◽  
R. B. Alley
Keyword(s):  
Shear Stress ◽  
Stress Drop ◽  
Fast Moving ◽  
Fault Plane ◽  
Spatial Density ◽  
Ice Stream ◽  
Slow Moving ◽  
Ice Stream B ◽  
Basal Shear ◽  
Plane Area

Microearthquakes at the base of slow-moving Ice Stream C occur many times more frequently than at the base of fast-moving Ice Stream B. We suggest that the microearthquake source sites are so-called “sticky spots”, defined as limited zones of stronger Subglacial material interspersed within a weaker matrix. The fault-plane area of the microearthquakes (O(102m2)) is therefore a measure of the size of the sticky spots. The spatial density of the microearthquakes (O(10 km-2)) is a measure of the distribution of sticky spots.The average stress drop associated with these microearthquakes is consistent with an ice-stream bed model of weak subglacial till interspersed with stronger zones that support much or all of the basal shear stress. We infer a weak inter-sticky-spot material by the large distances (O(103m)), relative to fault radius, to which the microearthquake stress change is transmitted.

scholarly journals Representation Theorem and Green’s Function (2)

2016 ◽  
Vol 68 (6) ◽  
pp. 169-176 ◽  
Author(s):  
Tetsuya KUSAKABE ◽  
Nobuki KAME ◽  
Mie ICHIHARA ◽  
Hiroyuki KUMAGAI
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Representation Theorem

Une nouvelle équation intégrale pour l'étude de la radiation scalaire dans une cavité

1978 ◽  
Vol 56 (3) ◽  
pp. 387-394 ◽  
Author(s):  
Byron T. Darling ◽  
Jacques A. Imbeau
Keyword(s):  
Integral Equation ◽  
Analytic Solution ◽  
Normal Derivative ◽  
Prolate Spheroidal ◽  
Equation Intégrale ◽  
Closed Cavity ◽  
Field Point ◽  
Special Cases ◽  
Limit Form ◽  
Dipole Sources

We derive an integral equation of the first kind connecting the surface values and the normal derivative for a regular solution inside a closed cavity of the Helmholtz equation. This integral equation has two advantages over the usual limit form of integral equations where the field point must lie on the boundary and the kernel is singular, namely, the field point may be anywhere inside or outside the cavity, and the kernel is regular. Analytic solution of our integral equation is obtained for the special cases of monopole and of dipole sources at the center of a sphere (Dirichlet's condition). The next paper will apply this integral equation to prolate spheroidal cavities.

scholarly journals Size and orientation of the fault plane for the 2001 Gujarat, India earthquake (Mw7.7) from aftershock observations: A high stress drop event

2002 ◽  
Vol 29 (20) ◽  
pp. 10-1-10-4 ◽  
Author(s):  
H. Negishi ◽  
J. Mori ◽  
T. Sato ◽  
R. Singh ◽  
S. Kumar ◽  
...  
Keyword(s):  
Stress Drop ◽  
Fault Plane ◽  
High Stress
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