Annual Hanford Seismic Report for Fiscal Year 2007.

Rohay, A. C. ; Sweeney, M. D. ; Hartshorn, D. C. ; Clayton, R. E. ; Devary, J. L.

Technical Information Center Oak Ridge Tennessee

关键词: Seismology;    Hanford Reservation;    Seismic events;    Earthquakes;    Monitoring;   

RP-ID  :  DE2008921585

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The Hanford Seismic Assessment Program (HSAP) provides an uninterrupted collection of highquality raw and processed seismic data from the Hanford Seismic Network for the U.S. Department of Energy and its contractors. The Hanford Seismic Assessment Team locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for waste management, natural phenomena hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of a significant earthquake on the Hanford Site. The Hanford Seismic Network and the Eastern Washington Regional Network consist of 41 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Assessment Team. During fiscal year 2007, the Hanford Seismic Network recorded 1254 triggers on the seismometer system, which included 134 seismic events in the southeast Washington area and an additional 421 regional and teleseismic events. There were 85 events determined to be local earthquakes relevant to the Hanford Site. The highest-magnitude event (2.3 Mc) occurred on March 20, 2007. The earthquake was considered a random event, with epicenter located approximately 20 km west of Othello, Washington, and focus within the crystalline basement. Stratigraphically, 42 earthquakes were located in the Columbia River Basalt Group (approximately 04 km depth), 13 earthquakes were located in the prebasalt sediments (approximately 58 km depth), and 30 earthquakes were located in the crystalline basement (approximately 925 km depth). Geographically, 52 earthquakes were located within swarm areas, and 32 earthquakes were classified as random events. One earthquake was located near a geologic structure (Saddle Mountain anticline). The Hanford strong motion accelerometer (SMA) network was triggered once during fiscal year 2007. The 300 Area and the 400 Area SMAs detected the 2.0-Mc seismic event that occurred on April 16, 2007. The 400 Area SMA recorded a maximum vertical acceleration of 0.25% g and a maximum horizontal acceleration of 0.23% g. The reportable action level for Hanford facilities (2% g) is approximately eight times larger than the peak accelerations recorded at the 400 Area, and no action was required.