Regional Centroid-Moment-Tensor Analysis for Earthquakes in Canada and Adjacent Regions: An Update
| Autor: | Catherine R. D. Woodgold, Garry C. Rogers, Shao-Ju Shan, Allison L. Bent, John F. Cassidy, Honn Kao, John Ristau |
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| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Seismological Research Letters. 83:505-515 |
| ISSN: | 1938-2057 0895-0695 |
| Popis: | Reliable determination of earthquake source parameters is a subject of fundamental importance for seismological research. It also provides critical observational constraints to the study of deformation and stress within the lithosphere. A comprehensive catalog of earthquake source parameters is not only essential to the understanding of global and regional tectonics, but also offers critical information on geological structures that may have engineering, economic, and hazard implications. In addition to the origin time, hypocenter, and magnitude, an earthquake’s source parameters include its focal mechanism, source time function, and the spatiotemporal distribution of slip. However, unless the source dimension is considerably larger than the wavelengths of propagating seismic waves ( e.g., P or S ), the source time function and slip distribution of a seismic event are difficult to resolve, meaning that it is effectively a point-source. The focal mechanism, on the other hand, is directly related to fault movement in the source region and can be determined by several different methods even if the event is an effective point-source. The simplest way to determine an earthquake’s focal mechanism is the “first-motion” method that derives the orientation of the fault plane (strike and dip) and the relative movement between the hanging wall and the foot wall (rake) from the polarity and distribution of first arrivals on the focal sphere (Aki and Richards 1980). A big drawback of this method is that it needs a large number of well-distributed stations with good data quality to sufficiently cover the focal sphere. The process of picking first arrivals and determining their polarity of motion can also be time-consuming, labor-intensive, and often ambiguous, even for well-experienced data analysts. One breakthrough in seismology during the past several decades was the realization that a seismic source can be mathematically represented by a moment tensor consisting of six independent elements (Aki … |
| Databáze: | OpenAIRE |
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