--------------------------------------------------------------- 02/22/2004 Egill Hauksson This (sc_84_02_dd3d_v1.71) is a relocated catalog from SCSN for 1984 to 2002. We have combined both HypoDD and locations determined using 3D velocity models to assemble a complete catalog. The use of differential travel times from cross-correlation of waveforms is new and improves the clustering of the hypocenters. If an earthquake hypocenter was rejected by hypoDD, we include the hypocenter from SIMULPS, determiend using a 3D velocity model. The recommended use of this catalog is for analyzing spatial and temporal seismicity patterns. The magnitudes available from the SCEDC may be more up to date. Any statistical research should be double checked by using magnitudes from the SCEDC. This catalog differs from the catalog SHLK_1.0 by Shearer et al. 2004 in two respects. First the SHLK_1.0 catalog uses different codes to relocate the earthquakes. Second, the SHLK_1.0 catalog includes quarry blasts that were mostly excluded from this catalog (sc_84_02_dd3d_v1.71). Relocations done by Egill Hauksson, and released in February 2004 If you use these locations, please reference: Hauksson et al., 2003. --------------------------------------------------------------- Methods: 1) Using program SIMULPS (Thurber 1993) and a 3D Vp and VP/Vs velocity model, derived from Hauksson(2000). These locations are labeled '3D' in positions 138:139 1984 1 1 120 0.77 35n59.39 118w25.81 4.53 0.65 7 34.4 0.19 13.8 99.0 -66.72 180.07 4.53 28254 3D Cols. Format Data _____ ______ ____ 1- 4 14 Year 5- 8 2I2, 1X month, day. 10- 13 2I2 Hour and minute. 14- 19 F6.2 Origin time seconds. 20- 22 F3.0 Latitude (deg). 23- 23 A1 S for south, blank or N for north 25- 28 F5.2 Latitude (min). 29- 32 F4.0 Longitude (deg). 33- 33 A1 E for east, blank otherwise. 34- 38 F5.2 Longitude (min). 39- 45 F7.2, 2X Depth (km). 48- 52 F5.2 Magnitude. See col. 80 for code 53- 55 I3 Number of P & S times with weights greater than 0.1. 60- 64 F5.1 Distance to nearest station (km). 65- 69 F5.2 RMS travel time residual. 70- 74 F5.1 Horizontal error (km). 75- 82 F7.2 Vertical error (km). 83- 90 F7.2 x-coordinate (km). 91- 98 F7.2 y-coordinate (km). 99-106 F7.2 z-coordinate (km). ===================================================================== 2) Using program HypoDD and a 1D velocity Model These locations are labeled 'DD' in positions 138:139 1984 1 1 025 8.51 34n 3.87 117w14.13 17.67 1.40 0.01 0.05 0.10 28253 28 32 187 57 DD Velocity Model used: *Model from Egill 5/3/01generic SOCAL velocity model 0.0 4.0 6.0 8.0 12.0 16.0 20.0 32.0 4.80 5.78 6.15 6.30 6.44 6.54 6.72 7.76 Duplicate solutions have been removed. Quarries and blasts are not included. Unstable hypocenters deepr than 30 km have been removed Cols. Format Data _____ ______ ____ 1- 4 14 Year 5- 8 2I2, 1X month, day. 10- 13 2I2 Hour and minute. 14- 19 F6.2 Origin time seconds. 20- 22 F3.0 Latitude (deg). 23- 23 A1 S for south, blank or N for north 25- 28 F5.2 Latitude (min). 29- 32 F4.0 Longitude (deg). 33- 33 A1 E for east, blank otherwise. 34- 38 F5.2 Longitude (min). 39- 45 F7.2, 2X Depth (km). 48- 52 F5.2 Magnitude. See col. 80 for code 65- 69 F5.2 RMS travel time residual. See also, HypoDD manual. 70- 74 F5.1 Horizontal error (km). See also, HypoDD manual. 75- 79 F5.1, 2X Vertical error (km). See also, HypoDD manual. 112 - 117 i6 nccp, nccs number of cross-correlated p and s data 118 - 123 i6 122 - 130 i6 nctp, ncts number of catalog p and s data 131 - 137 i6 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Hauksson, E. , Crustal structure and seismicity distributions adjacent to the Pacific and north America plate boundary in southern California, J. Geophys. Res , 105, 13,875-13,903, 2000. Hauksson E., W-C. Chi, P. Shearer, and A. Michael, Comprehensive waveform cross-correlation of southern California seismograms: Part 1. Refined hypocenters obtained using the double-difference method and tectonic implications (abstract), Fall. Ann. Meeting, American Geophys. Un., Dec. 8-12, 2003, San Francisco CA. Thurber, C. H., Local earthquake tomography: Velocities and Vp/Vs-Theory, in Seismic Tomography: Theory and Practice, edited by H. M. Iyer and K. Hirahara, pp. 563-583, Chapman and Hall, London, 1993. Waldhauser, F., hypoDD-A Program to Compute Double-Difference Hypocenter Locations (hypoDD version 1.0-3/2001, Open File Report 01-113, 2001. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++