High-Resolution Three-Dimensional Seismic Imaging of The Baikal and Amur Regions of Eastern Russia
Abstract
Eastern Russia is composed of a series of allochthonous terranes which have accreted to the Precambrian Siberian (North Asian) craton. This study is focused on the southern part (Baikal and Amur regions), where accretionary terranes form a suture zone between the Siberian and North China cratons, which is being exploited by the present-day boundary between the Eurasian plate and the Amur block. The complexities of accretion and subsequent intracontinental deformation likely result in a highly heterogeneous crust, a broad zone of deformation, and the formation of small blocks within the ancient suture and present-day plate boundary zones. We assembled catalog picks from ~13000 events and ~100 stations for the Baikal and Amur regions in the period of 1970 to 2005. Using the double-difference tomography method (Zhang and Thurber, 2003, 2006), our study for the first time provides a detailed seismic velocity model of the crust and upper mantle for this complicated area. The original sources for the Siberia database vary from published Siberia-wide Russian earthquake bulletins to unpublished bulletins of regional network operators. It is very likely that there still exist some arrival time pick outliers in the assembled data. Quality assessment of picks and event-pair differential times is a critical aspect for achieving a high-quality velocity model for the Baikal and Amur regions. In our study we identify and remove outliers in catalog picks using event-pair differential times based on the fact that travel times from two nearby events should be consistent. In our data set, many arrivals at larger distances are identified in the catalog as Pg or Sg phases, which are often observable because of their relatively large amplitudes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2007
- Accession Number
- ADA519678
Entities
People
- Charlotte A. Rowe
- Clifford H. Thurber
- Haijiang Zhang
- Kazuya Fujita
- Kevin G. Mackey
- Lee K. Steck
- Steven Roecker
Organizations
- University of Wisconsin–Madison