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1975年夏威夷卡拉帕纳地震发生在变化无常的基拉韦厄火山南翼之下。对此次地震有不同的解释,如正断层地震、冲断层地震以及山崩。最初的崩塌模式的证据是先前的断层模式不能解释由卡拉帕纳事件产生的勒夫波辐射图型和海啸振幅。在此, 我们对该事件的长周期数字地震数据进行再分析。矩心矩张量分析显示该地震辐射图型能被充分地解释为由一个向陆浅倾的冲断层引起。我们测定的地震矩为3．8×1020 Nm (Mw7．7),大约为早先估计的2倍。本研究中,震源机制解确定的构造和地震矩与观测到的海啸振幅是一致的。长周期的体波波形的反演显示这次震源持续时间(-72 s)对于一次这样大小的地震来说显得异乎寻常地长。
The 1975 earthquake in Carapana, Hawaii, took place under the volatile south wing of the Kilauea volcano. There are different interpretations of this earthquake, such as normal fault, thrust and earthquake. The first evidence of a collapse pattern is that the previous fault pattern did not explain the Love wave radiation patterns and tsunami amplitudes produced by the Calapana event. Here, we reanalyzed the long-period digital seismic data of this event. Tensor moment tensor analysis shows that the seismic radiation pattern can be fully interpreted as a shallow fault thrusting to the surface. We measured a seismic moment of 3.8 × 1020 Nm (Mw7.7), about twice the earlier estimate. In this study, the focal tectonic and seismic moments determined by focal mechanism solutions are consistent with the observed amplitudes of tsunamis. The inversion of the long-period body-wave waveform shows that the source duration (-72 s) is unusually long for an earthquake of this magnitude.