Recent earthquake activity in the Snowy Moutains region and its relationship to major faults
Titel:
Recent earthquake activity in the Snowy Moutains region and its relationship to major faults
Auteur:
Bock, Gunter Denham, David
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 30 (1983) nr. 3-4 pagina's 423-429
Jaar:
1983-12
Inhoud:
The seismicity of the Snowy Mountains region, which is situated between 36° to 37°S and 148° to 149°E, was studied for the period June 1971 to February 1982. Most earthquake epicentres seem to correspond to major faults. The 1971 Middlingbank earthquakes, on the other hand, were located in a region where no major faults have been mapped. Focal mechanisms could be determined for three earthquakes: the 1981 Suggan Buggan earthquake, which was probably associated with the Moyangul River Fault and was of strike-slip type; the nearby earthquake beneath the Pilot mountain, which occurred in 1976 and was a thrust-faulting event; and the 1971 Middlingbank earthquake series that took place a few kilometres south of Lake Eucumbene and was associated with right-lateral strike-slip faulting along an east trending plane. Although these earthquakes were associated with different types of faulting, they were all probably caused by horizontal compressive stresses in the crust acting along an azimuth of about 120°, thus confirming previous investigations of crustal stresses made in southeastern Australia. The 1971 Middlingbank earthquakes may have been associated with the filling of Lake Eucumbene, because the maximum water level up to that time was reached in December 1970. However, the influence of the reservoir cannot be properly assessed.
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