Using Dynamic and Kinematic models to Evaluate the Back Projection Results
Abstract
Since its first application to study the rupture process of the 2004 Mw 9.2 Sumatra earthquake, the back projection method has been widely applied to image the rupture process of many large earthquakes and moderate earthquakes. However, it is debatable whether the peak beam power in the back projection result represents the average location rupture front during that time window, as commonly believed. In addition, there are other critical questions - relevant to interpretation of the back projection results - that remain unanswered. Some of the important ones are - why different arrays often show different rupture features? Why the rupture shows frequency dependent propagation? How do we distinguish between rupture jump and increase in rupture velocity? In this project, we design dynamic and kinematic models, in which we know exactly the spatiotemporal evolution of the rupture process. Then we use the configuration of current global arrays, and a few artificial arrays to calculate synthetic seismograms from the modeling results. Then we use the receiver arrays to back project the rupture process of the model events. Finally, we compare the back projection results with the dynamic models. Such comparisons using multiple models and their back projection results using multiple arrays demonstrate some similar characteristics. First, the back projection results show generally slower rupture velocity than the dynamic models. Second, depending on the rupture directions and array locations, the arrays on different azimuths can show different rupture propagations, especially when the events rupture in different directions or have branch ruptures. Third, rupture velocity changes will result in higher amplitude in the seismograms, which will lead to stronger beam power in the back projection results. More dynamic and kinematic models will be designed to help us better understand the physical meaning of the back projection results and better interpret the back projection results.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.S43C0606L
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGYDE: 7215 Earthquake source observations;
- SEISMOLOGYDE: 7230 Seismicity and tectonics;
- SEISMOLOGYDE: 7260 Theory;
- SEISMOLOGY