Faulting associated with the major north Solomon Sea earthquakes of 14 and 26 July 1971
Titel:
Faulting associated with the major north Solomon Sea earthquakes of 14 and 26 July 1971
Auteur:
Everingham, I. B.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 22 (1974) nr. 1 pagina's 61-69
Jaar:
1974-04
Inhoud:
Major tsunamigenic earthquakes occurred on 14 July and 26 July 1971 about 100 km apart in the north Solomon Sea. The second earthquake is not considered to be an aftershock of the first: aftershock patterns and fault-plane solutions indicate that both were the result of movements along two separate parts of a major arcuate fault surface. The first earthquake caused movement along the part of the fault that extends south-southeast, the second in the part that extends west-southwest, from southernmost New Ireland. The two aftershock zones overlapped to the south-southeast of New Ireland near the epicentre of the 26 July earthquake and where its fault rupture commenced. The rupturing was probably due to the effects of the 14 July earthquake series. Aftershock and first-motion data indicate that the area between Bougainville Island, southern New Ireland, and southeastern New Britain is being underthrust from the south. The fault surface appears to be concave downwards, with depth and dip increasing towards the islands to the northwest, north, and northeast. During both earthquakes, intensities of at least MM8 were experienced; their isoseismals form ellipses whose long axes coincide with the trend of the relevant aftershock zone (i.e., south-southeast for the first earthquake, west-southwest for the second). Maximum intensities apparently occurred above the aftershock region. Evidence suggests a surface-wave magnitude of 8.0 for both earthquakes.
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