Love wave tomography in Italy from seismic ambient noise
Hongyi Li1, 2, Fabrizio Bernardi3, Alberto Michelini3
1 Key Laboratory of Geo-detection (China University of Geosciences, Beijing), Ministry of Education, Beijing 100083, China 2 School of Geophysics and Information Technology, China University of Geosciences, Beijing 100083, China 3 Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, Rome 00143, Italy
Love wave tomography in Italy from seismic ambient noise
Hongyi Li1, 2, Fabrizio Bernardi3, Alberto Michelini3
1 Key Laboratory of Geo-detection (China University of Geosciences, Beijing), Ministry of Education, Beijing 100083, China 2 School of Geophysics and Information Technology, China University of Geosciences, Beijing 100083, China 3 Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, Rome 00143, Italy
摘要We estimate Love wave empirical Green’s functions from cross-correlations of ambient seismic noise to study the crust and uppermost mantle structure in Italy. Transverse-component ambient noise data from October 2005 through March 2007 recorded at 114 seismic stations from the Istituto Nazionale di Geofisica e Vulcanologia (INGV) national broadband network, the Mediterranean Very Broadband Seismographic Network (MedNet) and the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) yield more than 2 000 Love wave group velocity measurements using the multiple-filter analysis technique. In the short period band (5-20 s), the cross-correlations show clearly one-sided asymmetric feature due to non-uniform noise distribution and high local activities, and in the long period band (>20 s) this feature becomes weak owing to more diffusive noise distribution. Based on these measurements, Love wave group velocity dispersion maps in the 8-34 s period band are constructed, then the SH wave velocity structures from the Love wave dispersions are inverted. The final results obtained from Love wave data are overall in good agreement with those from Rayleigh waves. Both Love and Rayleigh wave inversions all reveal that the Po plain basin is resolved with low velocity at shallow depth, and the Tyrrhenian sea is characterized with higher velocity below 8 km due to its thin oceanic crust.
Abstract：We estimate Love wave empirical Green’s functions from cross-correlations of ambient seismic noise to study the crust and uppermost mantle structure in Italy. Transverse-component ambient noise data from October 2005 through March 2007 recorded at 114 seismic stations from the Istituto Nazionale di Geofisica e Vulcanologia (INGV) national broadband network, the Mediterranean Very Broadband Seismographic Network (MedNet) and the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) yield more than 2 000 Love wave group velocity measurements using the multiple-filter analysis technique. In the short period band (5-20 s), the cross-correlations show clearly one-sided asymmetric feature due to non-uniform noise distribution and high local activities, and in the long period band (>20 s) this feature becomes weak owing to more diffusive noise distribution. Based on these measurements, Love wave group velocity dispersion maps in the 8-34 s period band are constructed, then the SH wave velocity structures from the Love wave dispersions are inverted. The final results obtained from Love wave data are overall in good agreement with those from Rayleigh waves. Both Love and Rayleigh wave inversions all reveal that the Po plain basin is resolved with low velocity at shallow depth, and the Tyrrhenian sea is characterized with higher velocity below 8 km due to its thin oceanic crust.
基金资助:the 2004-2006 National Civil Defense Project of Italy (DPC)-S4, 2007-2009 DPC-S3 and the Fundamental Research Funds for the Central Universities of China under grant No. 2010ZD06
通讯作者:
Hongyi Li
E-mail: lih@cugb.edu.cn
引用本文:
Hongyi Li, Fabrizio Bernardi, Alberto Michelini. Love wave tomography in Italy from seismic ambient noise[J]. 《地震学报》英文版, 2010, 23(5): 487-495.
Hongyi Li, Fabrizio Bernardi, Alberto Michelini. Love wave tomography in Italy from seismic ambient noise. Earthquake Science, 2010, 23(5): 487-495.
