Crustal and Upper-mantle Structures Beneath the Chinese Continent From Joint Inversion of Rayleigh-wave Group Velocities and Waveforms
Abstract
Traditional fundamental-mode surface wave dispersion tomography is the most common method used to study continental-scale lithosphere structures. But due to its limited resolution in deep upper mantle, most of previous models based on the fundamental-mode tomography can hardly offer information deeper than about 200 km. However, dispersion processing does not require event focal mechanisms, so it can be applied to smaller earthquakes and consequently has good path coverage. Surface waveform tomography is another useful way to study upper-mantle structures. Because of higher-mode content of the surface waveforms, surface waveform tomography gives better resolution in deep upper mantle. However, as waveform processing requires event focal mechanisms, waveform tomography can only be applied to strong earthquakes and consequently has worse path coverage. To strengthen the advantage and suppress the disadvantage of these two types of tomography, the present study derived a new method combining surface wave dispersion and waveform constraints in a 3D inversion. The final jointly inverted 3D S-velocity model is improved both in lateral resolution and resolution in depth which can be seen in checkerboard test results. The final S-velocity model can simultaneously fit both dispersion observations and waveform observations. The Chinese continent is an attractive region for geoscientists because of its diversity and complexity of geological evolutions. Upper mantle structure features revealed in our new model are well consistent with known geotectonic units.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFM.T13E1623F
- Keywords:
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- 7208 Mantle (1212;
- 1213;
- 8124);
- 7255 Surface waves and free oscillations;
- 7270 Tomography (6982;
- 8180);
- 9320 Asia