Seismic images under the Beijing region inferred from P and PmP data

Details Seismic images under the Beijing region inferred from P and PmP data Seismic images under the Beijing region inferred from P and PmP data

Jul 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008pepi..168..134l&link_type=abstract

Physics of the Earth and Planetary Interiors, Volume 168, Issue 3-4, p. 134-146.

Physics

9

Scientific paper

In this study a new tomographic method is applied to over 1500 high-quality PmP (Moho reflected wave) travel-time data as well as over 38,500 high-quality first P-wave arrivals to determine a detailed 3D crustal velocity structure under Beijing and adjacent areas. Results of detailed resolution analyses show that the PmP data can significantly improve the resolution of the model in the middle and lower crust. After the PmP data are included in the tomographic inversion, our new model not only displays the tectonic feature appeared in the previous studies, but also reveals some new features. The Zhangjiakou-Bohai Sea fault zone (Zhang-Bo zone) is imaged as prominent and continuous low-velocity (low-V) anomalies in the shallower crust, while in the middle and lower crust it shows intermittent low-V anomalies extending down to the uppermost mantle. Furthermore, the pattern of low-V anomalies is different along the Zhang-Bo zone from the southeast to the northwest, indicating that there exist large differences in the dynamic evolution of Taihangshan and Yanshan uplifts and North China depression basin. Prominent low-V anomalies are visible under the source area of the 4 July 2006 Wen-An earthquake (M 5.1), suggesting that the occurrence of the Wen-An earthquake is possibly related to the effect of the crustal fluids probably caused by the upwelling of the hot and wet asthenospheric materials due to the deep dehydration of the stagnant Pacific slab in the mantle transition zone. The fluids in the lower crust may cause the weakening of the seismogenic layer in the upper and middle crust and thus contribute to the initiation of the Wen-An earthquake. This is somewhat similar to the cause of the 1695 Sanhe-Pinggu earthquake and the 1976 Tangshan earthquake in the region, as well as the 1995 Kobe earthquake in Japan and the 2001 Bhuj earthquake in India.

Affiliated with

Also associated with

No associations

Rating

Seismic images under the Beijing region inferred from P and PmP data does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Seismic images under the Beijing region inferred from P and PmP data, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Seismic images under the Beijing region inferred from P and PmP data will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-787618