Modeling the Near-Field Terms of Deep Earthquakes: Possible Constraints on the Mechanics of Rupture

9814822Wallace这项研究涉及大地震破裂的中近场项的发展，并将其应用于1994年玻利维亚深层大地震（震级8.3，636公里，1994年6月9日）。 现代宽带地震仪器已经彻底改变了地震学，并允许在几乎任何地震感兴趣的频带中检索信息。 通过偶然的机会，PASSCAL便携式宽带地震实验“捕获”了地震上方的静态位移以及P波和S波之间的长周期波。 这些信号可以解释为与剪切位错相关的位移场的中间场和近场项。 自1994年地震以来，又发现了16个以上的深源地震，它们产生了类似的中近场项。 由于这些术语取决于地震矩的时间演化，而不是矩率（如在远场地震信号中观察到的），因此对这些术语进行建模可以为地震力学提供新的见解。 这项研究是国家地震减灾计划的一个组成部分。

9814822Wallace This research involves the development of intermediate- and near-field terms for large earthquake ruptures and application of this to the 1994 deep great Bolivian earthquake (magnitude 8.3, 636-km depth, 9 June 1994). Modern broadband seismic instrumentation has revolutionized seismology and allowed the retrieval of information in almost any frequency band of seismic interest. Through serendipity, a PASSCAL portable broadband seismic experiment "captured" the static displacement just above the earthquake as well as very long period waves between the P and S waves. These signals may be interpreted as the intermediate- and near-field terms of the displacement field associated with a shear dislocation. Since the1994 event, more than 16 additional deep earthquakes have been identified which produced similar intermediate- and near-field terms. Since these terms depend on the temporal evolution of the seismic moment rather than the moment rate (as is observed in far-field seismic signals), modeling these terms could provide new insights into the mechanics of earthquakes. This research is a component of the National Earthquake Hazard Reduction Program.