Determination of Source Parameters

Alongside the determination of the focal mechanism and source depth of an earthquake by direct examination of their probable values on a grid in the parameter space, also the resolution of these determinations can be estimated. However, this approach requires considerable time in the case of a detailed search. A special case of a shallow earthquake whose one nodal plane is subhorizontal is an example of the sources that require the use of a detailed grid. For studying these events based on the records of the long-period surface waves, the grids with high degree of detail in the angles of the focal mechanism are required. We discuss the application of the methods of parallel computing for speeding up the calculations of earthquake parameters and present the results of studying the strongest aftershock of the Tohoku, Japan, earthquake by this approach.

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Determination of source parameters of small earthquakes from P-wave rise time

Bulletin of the Seismological Society of America ◽

10.1785/bssa0630020599 ◽

1973 ◽

Vol 63 (2) ◽

pp. 599-614 ◽

Cited By ~ 4

Author(s):

M. E. O'Neill ◽

J. H. Healy

Keyword(s):

Rise Time ◽

Source Parameters ◽

P Wave ◽

Simple Method ◽

Zero Crossing ◽

Basic Measurement ◽

Earthquake Source Parameters ◽

Short Period ◽

Stress Drops

abstract A simple method of estimating source dimensions and stress drops of small earthquakes is presented. The basic measurement is the time from the first break to the first zero crossing on short-period seismograms. Graphs relating these measurements to rise time as a function of Q and instrument response permit an estimate of earthquake source parameters without the calculation of spectra. Tests on data from Rangely, Colorado, and Hollister, California, indicate that the method gives reasonable results.

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Source parameter determination of local earthquakes in Korea using moment tensor inversion of single station data

Bulletin of the Seismological Society of America ◽

10.1785/bssa0890041077 ◽

1999 ◽

Vol 89 (4) ◽

pp. 1077-1082 ◽

Cited By ~ 1

Author(s):

So Gu Kim ◽

Nadeja Kraeva

Keyword(s):

Moment Tensor ◽

Source Parameters ◽

Moment Tensor Inversion ◽

P Wave ◽

Parameter Determination ◽

Reverse Fault ◽

3D Tomography ◽

Single Station ◽

Slip Event

Abstract The purpose of this investigation is to determine source parameters such as focal mechanism, seismic moment, moment magnitude, and source depth from recent small earthquakes in the Korcan Peninsula using broadband records of three-component single station. It is very important and worthwhile to use a three-component single station in Korea because for most Korean earthquakes it is not possible to read enough first motions of P-wave arrivals because of the poor coverage of the seismic network and the small size (ML 5.0 or less) of the events. Furthermore the recent installation of the very broadband seismic stations in Korea and use of a 3D tomography technique can enhance moment tensor inversion to determine the source parameters of small earthquakes (ML 5.0 or less) that occur at near-regional distances (Δ ≤ 500 km). The focal solution for the Youngwol earthquake of 13 December 1996 is found to be a right-lateral strike slip event with a NE strike, and the Kyongju earthquake of 25 June 1997 is found to be an oblique reverse fault with a slight component of left-lateral slip in the SE direction.

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