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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.
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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).
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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
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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.
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