HR: 1340h
AN: S43A-1044    [Abstracts]
TI: Seismotectonics of the Pitcairn Island 2001-2002 Earthquake Sequence
AU: * Woods, M T
EM: mwoods@aftac.gov
AF: Air Force Technical Applications Center, 1030 South Highway A1A, Patrick AFB, FL 32925, United States
AU: Junek, W N
EM: wjunek@aftac.gov
AF: Air Force Technical Applications Center, 1030 South Highway A1A, Patrick AFB, FL 32925, United States
AB: Continued investigation of the Pitcairn Island earthquake swarm in the southcentral Pacific Ocean is revealing new details about that remarkable sequence. The period of intense activity commenced in October 2001 and continued through January 2002, for which over 10,000 events have been cataloged with a battery of automatic signal detection algorithms. These algorithms include matched filter and waveform cross-correlation techniques that are coupled with statistical tests of the significance of the correlation coefficients. Relative amplitude scaling against a large master event (2001 November 23; 10:32:26.4 UTC; mb ~ 4.0) allows assignment of a magnitude value to smaller events. The size distribution of earthquakes calculated throughout the sequence appears to vary with time, with the slopes ranging as -1.3 ≥ b ≥ -3.0 on a scale of days. This variation may indicate the interaction of volcanic and tectonic processes. Cluster analysis with dendrograms suggests multiple distinct sources, consistent with previously reported results (Hyvernaud et al., 2002; Peyton et al., 2002). Although attempts at deriving moment tensors have not yet succeeded, modeling waveforms recorded at PTCN bracket the range of source depths as between 8 and 32 km.
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 7280 Volcano seismology (8419)
DE: 8137 Hotspots, large igneous provinces, and flood basalt volcanism
DE: 8415 Intra-plate processes (1033, 3615)
SC: Seismology [S]
MN: 2007 Fall Meeting