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Source Characterization of the October 30, 1983 Narman-Horasan Earthquakeby Submitted to the Department of Earth, Atmospheric, and Planetary Sciences on September 1, 1985 in partial fulfillment of the requirements for the degree of Master of Science ABSTRACT
Source parameters are determined for the October 30, 1983, Narman-Horasan
earthquake in northeastern Turkey, Ms = 6.9, using far-field body wave and near-field
synthetic seismograms. A double-couple point source is obtained from the inversion
of teleseismic P and SH long period WWSSN and GDSN data. The preferred source
mechanism is left lateral strike-slip with a small thrust component (strike =
215°, dip =64°, slip =7°). The centroid depth is estimated at 10 km
and the seismic moment at 8.0X1025 dyn-cm. The duration of the source time function
is approximately 5 s. Dimensions of an assumed rectangular fault are determined
from the point source solution and aftershock distribution. Fault width is estimated
at 13 km and length at 15 km. Based on these values the average displacement on
the fault is 1.2 m. It is speculated that source region structure is responsible
for the complicated nature and long duration of the body wave records. Forward
modeling of the single three-component strong motion record from a station 25
km south of the epicenter is carried out using a discrete wavenumber calculation.
The study reveals that the rupture to the southwest, propagating at sub-shear
velocity, explains the outstanding characteristics of the processed displacement
records. A to 1 km thick low velocity surface layer representing sedimentary cover
is an essential part of the model. Return to Theses Return to ERL Home Updated: June, 1999
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