HR: 1340h
AN: S23B-1382    [Abstracts]
TI: Global Travel Time Tomography and Earthquake Relocation With a 3-D Reference Model
AU: * Amaru, M
EM: amaru@geo.uu.nl
AF: Department of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD, Netherlands
AU: Spakman, W
EM: wims@geo.uu.nl
AF: Department of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD, Netherlands
AU: Villasenor, A
EM: antonio@ija.csic.es
AF: Department of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD, Netherlands
AU: Villasenor, A
EM: antonio@ija.csic.es
AF: Institute of Earth Sciences "Jaume Almera", CSIC, Lluis Sole i Sabaris s/n, Barcelona, 08028, Spain
AB: Aim of this study is to obtain a high-resolution tomography model of the Earth's mantle. This new model helps to get a better understanding of the tectonic and geodynamic evolution of the Earth and can be used to improve travel time prediction and earthquake location. Improvements of our 3-D tomography model compared to previous models are achieved by incorporating new data from stations in Europe and North America in an existing global travel time data set. Furthermore, we advanced the tomographic method to use a 3-D reference model instead of a standard 1-D Earth reference model. The 3-D reference model is based on a combination of tomography models that use travel times and models that use independent observations from surface waves, normal modes and long period body waves. Compared to previous models using a similar method, more detail is seen in the resulting tomography model in the upper 400 km of the mantle due to the new data and additional core phases help to constrain anomalies in the lowermost mantle. The resulting model combines the long wavelength structure as "seen" by long period seismic information contained in the 3-D reference model with the detailed mantle structure obtained from short period data during inversion. Tests with well located events show that the new tomography model predicts, particularly at regional distances, arrival times better than a 1-D velocity model and that the epicenter location errors are reduced. As a final step, the new tomography model has been used to relocate a global earthquake data set with respect to that model. Thereby, earthquake locations are corrected for 3-D Earth structure not taken into account by the original location process using a standard 1-D Earth reference model. In addition a better focusing of earthquakes in narrower clusters is achieved due to the new tomography model, in particular, in the deeper parts of subducted slabs (> 150 km).
DE: 7203 Body waves
DE: 7208 Mantle (1212, 1213, 8124)
DE: 7270 Tomography (6982, 8180)
SC: Seismology [S]
MN: 2007 Fall Meeting