Tsnunami Earthquakes and Interplate Coupling at Subduction Zones

9316528 Kanamori 这项研究旨在研究引发海啸的地震的特征，以确定板块边缘沉积物俯冲的作用以及由此产生的对俯冲带地震机制的影响。 将对 1992 年尼加拉瓜地震和其他俯冲带地震进行详细调查，以确定与各事件震中附近沉积物结构相关的震源特征和频谱。 除了传统的地震分析之外，该研究还将涉及使用新认识的长周期相位，即 W 相位，它到达 P 波和 S 波之间。 传统的海啸预警系统基于地震的位置和震级。 不幸的是，由于过去仪器的限制，传统系统使用 20 秒表面波震级来进行警告。 然而，对于像尼加拉瓜事件这样的慢震，20秒的面波震级并不能代表地震的真实大小。 如果持续时间超过 100 秒，人们就能更好地认识到海啸的可能性。 这项研究是国家地震减灾计划的一部分。 ***

9316528 Kanamori This research is to study the characteristics of tsunami- producing earthquakes to determine the role of sediment subduction at plate margins and the resulting influence on the mechanism of subduction-zone earthquakes. Detailed investigations of the 1992 Nicaragua earthquake and other subduction-zone earthquakes will be done to determine the source characteristics and spectra in relation to the sediment structure near the epicenter of the respective events. In addition to traditional seismic analysis, the research will involve use of a newly recognized long-period phase, the W phase, which arrives between the P and S waves. The traditional tsunami warning system is based on the location and the magnitude of the earthquake. Unfortunately, because of past instrumental limitations, the traditional system uses 20-second surface-wave magnitude for warning purposes. However, for slow earthquakes such as the Nicaragua event, the 20-second surface-wave magnitude does not represent the true size of the earthquake. At periods longer than 100 seconds, the tsunami potential would have been better recognized. This research is a component of the National Earthquake Hazard Reduction Program. ***