Seismicity in the vicinity of Yucca Mountain, Nevada, for the period October 1, 2003, to September 30, 2004

This report describes the seismicity and earthquake monitoring activities within the Yucca Mountain region during fiscal year 2004 (FY2004 - October 1, 2003, through September 30, 2004) based on operation of the Southern Great Basin Digital Seismic Network (SGBDSN). Network practices and earthquake monitoring conducted at the Nevada Seismological Laboratory (NSL) under DOE directives for prior fiscal years are covered in similar yearly reports (see references). Real-time systems, including regional data telemetry and data management at NSL, provide for the automatic determination of earthquake locations and magnitudes and notification of important earthquakes in the region to UNR staff and DOE management. All waveform and meta-data, including automatic locations, phase arrival information, and analyst reviewed information, are managed through a relational database system allowing quick and reliable evaluation and analysis of ongoing earthquake activity near Yucca Mountain. This network, which contains weak-motion and strong-motion instrumentation, addresses the seismic hazard of the Yucca Mountain area by providing accurate earthquake magnitudes for earthquake recurrence estimates, spatial hypocentral control to very low magnitudes for identifying and assessing active faults and verifying tectonic models, true ground motions over the complete range of expected earthquake amplitudes for developing predictive models, and earthquake source information for characterizing active faulting