SURFACE FAULT TRACES AND HISTORICAL EARTHQUAKE EFFECTS NEAR LOS ALAMOS VALLEY, SANTA BARBARA COUNTY, CALIFORNIA P.D. Guptill, E.G. Heath, and G.E. Brogan Woodward-Clyde Consultants 4000 West Chapman Avenue Orange, California 92668 USGS CONTRACT NO. 14-08-0001-18255 Supported by the EARTHQUAKE HAZARDS REDUCTION PROGRAM OPEN-FILE NO. 81-271 U.S. Geological Survey OPEN FILE REPORT This report was prepared under contract to the U.S. Geological Survey and has not been reviewed for conformity with USGS editorial standards and stratigraphic nomenclature. Opinions and conclusions expressed herein do not necessarily represent those of the USGS. Any use of trade names is for descriptive purposes only and does not imply endorsement by the USGS. SURFACE FAULT TRACES AND HISTORICAL EARTHQUAKE EFFECTS NEAR LOS ALAMOS VALLEY, SANTA BARBARA COUNTY, CALIFORNIA By P. D. Guptill, E. G. Heath/ and G. E. Brogan Woodward-Clyde Consultants 4000 West Chapman Avenue Orange/ California 92668 FINAL TECHNICAL REPORT November 1980 SPONSORED BY THE U.S. GEOLOGICAL SURVEY Contract No.: 14-08-0001-18255 Co-Principal Investigators: George E. Brogan Edward G. Heath Government Technical Officer Gordon W. Greene U.S. Geological Survey 345 Middlefield Road Menlo Park, CA 94025 Effective Date of Contract: 20 June 1979 Contract Expiration Date: 19 October 1980 Amount of Contract: $38/574 Date: 5 November 1980 The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. TABLE OF CONTENTS Page TABLE OF CONTENTS LIST OF FIGURES, PLATES, AND TABLES ABSTRACT 1.0 INTRODUCTION ................................. 1 2.0 BACKGROUND INFORMATION ....................... 3 2.1 Location and Setting of Study Area ...... 3 2.2 Seismicity .............................. 4 2.3 Previous Work ........................... 4 3.0 METHODS OF STUDY ............................. 6 4.0 RESULTS OF INVESTIGATION ..................... 9 4.1 Historical Data, 1902 and 1915 Earthquakes ........................ 9 4.1.1 1902 Los Alamos Earthquakes ...... 9 4.1.2 1915 Los Alamos Earthquakes ...... 15 4.2 Stratigraphy ............................ 16 4.2.1 Paso Robles Formation ............ 23 4.2.2 Orcutt Sand ...................... 24 4.2.3 Younger Strath Terrace Deposits .. 25 4.3 Aerial Photographic Fault and Lineament Interpretation ................ 27 4.3.1 Baseline Fault ................... 27 4.3.2 Los Alamos Fault ................. 29 4.3.3 Solomon Canyon Fault ............. 30 4.3.4 Northern Baseline Lineament ...... 30 Page 4.4 Field Mapping and Geomorphic 31 Interpretations ......................... 4.4.1 Baseline Fault ................... 31 4.4.2 Los Alamos Fault ................. 35 4.4.3 Northern Baseline Fault .......... 40 4.5 Trench Excavations ...................... 42 5.0 CONCLUSIONS AND OBSERVATIONS ................. 48 6.0 FUTURE WORK AND RECOMMENDATIONS .............. 52 REFERENCES ........................................ 54 APPENDIX A EARTHQUAKE CATALOG APPENDIX B SOURCES OF HISTORICAL DATA APPENDIX C NEWSPAPER CLIPPINGS, LOS ALAMOS EARTHQUAKES, 1902 AND 1915 APPENDIX D HISTORICAL ACCOUNTS OF LOS ALAMOS EARTHQUAKES (Townley and Alien, 1939) LIST OF FIGURES, PLATES, AND TABLES Page Figures 1 AERIAL PHOTOGRAPHIC LINEAMENT AND FAULT MAP ......................... 2 2 SEISMICITY MAP, 1925 THROUGH DECEMBER 1978 ......................... 5 3 TRENCH AND TEST PIT LOCATION MAP ...... 10 4 LOCATION OF GEOLOGIC EFFECTS FROM 1902 AND 1915 EARTHQUAKES ............. 11 5 PHOTO-GEOMORPHOLOGIC MAP, LOS ALAMOS- BASELINE FAULT TREND (6 sheets) ....... 17-22 6 SCHEMATIC DIAGRAM OF TERRACE SEQUENCE WITH RESPECT TO BASELINE FAULT ........ 33 7 STREAM THALWEG PROFILE, OFFSET ACROSS BASELINE FAULT, CRAWFORD RANCH ....................... 34 8 LOS ALAMOS FAULT SCARP ................ 37 9 TOPOGRAPHIC PROFILE LOCATION MAP, NORTHERN BASELINE FAULT ............... 41 10 TRENCH NO. 1 .......................... 43 11 TRENCH NO. 2 .......................... 44 12 TRENCH NO. 3 .......................... 45 13 TRENCH NO. 1 OFFSET SOIL .............. 47 14 TRENCH NO. 2 OFFSET SOIL .............. 49 15 TRENCH NO. 2 LOW-ANGLE SHEAR SURFACE ......................... 50 Plates (In Pocket) 1 TOPOGRAPHIC PROFILE, NORTHERN BASELINE LINEAMENT LIST OF FIGURES, PLATES, AND TABLES (CONT'D) Plates (cont'd) 2 (Sheet 1) TRENCH LOG, BARHAM RANCH SITE 1, LOS ALAMOS FAULT (Sheet 2) LITHOLOGIC DESCRIPTIONS, BARHAM RANCH, TRENCH 1 (Sheet 1) TRENCH LOG, BARHAM RANCH SITE 2 , LOS ALAMOS FAULT (Sheet 2) LITHOLOGIC DESCRIPTIONS BARHAM RANCH, TRENCH 2 Page Tables 1 GEOLOGIC EFFECTS REPORTED FROM THE 12 JULY 1902 EARTHQUAKES IN LOS ALAMOS AND VICINITY GEOLOGIC EFFECTS REPORTED FROM THE 13 JAN. 1915 EARTHQUAKES IN LOS ALAMOS AND VICINITY APPENDIX A EARTHQUAKE CATALOG PAGE: 1 CAT, DATE TIME(GMT) LAT LONG SL INTEN MAG SM H DIS Q S LOCATION A N D COMMENTS) NO. DAY-MO-YEAR HR-MIN-SEC (MM) (KM)(KM) 1 29 JUN 1925 14s42:16.0 34.300N 119.800W 6.25N' N ORIGINAL DATA SOURCE = GUT LOCAL MAGNITUDE =6.2? SCALE =ML AUTHORITY= PAS 14 JAN 1932 00:51:08.0 34.433N 119.866W 3.00N' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =3.00 SCALE =ML AUTHORITY- PAS 3 30 JAN 1932 00:48:58.0 34.916N 120.733W 3.00N' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EP.TCENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =3.00 SCALE =M AUTHORITY= PAS 4 13 MAR 1932 23:09:23.7 34.433N 120.183W 3.SON' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITB ORIGINAL DATA SOURCE - PAS LOCAL MAGNITUDE « 3.50 SCALE =ML AUTHORITY= PAS I 5 6 APR 1932 22:42:00.0 34.583N 120.750W 3.00N' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =3.00 SCALE -ML AUTHORITY= PAS 6 6 JUN 1933 18:17:33.0 34.283N 119.766W 3.00N' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =3.00 SCALE =ML AUTHORITY^ PAS 7 26 JUN 1933 06:25:42.0 34.333N 119.833W 4.30N' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITD ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE = 4.30 SCALE =ML AUTHORITY^ PAS 8 26 JUN 1933 06:27:52,0 34.333N 119.833U 4.30N' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITD ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =4.30 SCALE =ML AUTHORITY= PAS 9 19 MAY 1934 06:37:00.0 34.583N 120.750W 3.00N' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITD WOODWARD-CLYDE CONSULTANTS 30 OCT 80 PAGE 2 CAT. DATE TIME(GMT) LAT LONG SL INTEN MAG SM H DIS Q S LOCATION AND COMMENTS NO. DAY-MO-YEAR HR-MIN-SEC (MM) (KM)(KM) ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =3.00 SCALE =ML AUTHORITY= PAS 10 24 MAY 1934 06:52:00.0 34.416N 119.750U 2.SON' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE - 2.50 SCALE =ML AUTHORITY- PAS 11 24 MAY 1934 09:04:00.0 34.416N 119.750U 2.SON' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =2.50 SCALE -ML AUTHORITY= PAS 12 25 AUG 1934 18:52:00.0 34.416N 119.750U 2.SON' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE = 2.50 SCALE =ML AUTHORITY--; PAS > 13 17 DEC 1934 11:10:00.0 34.583N 120.333U 4.SON' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITB ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =4.50 SCALE =ML AUTHORITY^ PAS 14 17 DEC 1934 13:51:00.0 34.583N 120.333W 2.SON' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =2.50 SCALE =ML AUTHOR ITY-- PAS 15 17 DEC 1934 15:35:00.0 34.583N 120.333U 2.SON' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =2.50 SCALE =ML AUTHORITY** PAS 16 18 DEC 1934 03:09a00.0 34.583N 120.333U 4.00N' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE =4.00 SCALE =ML AUTHORITY= PAS 17 18 DEC 1934 04:34:00.0 34.583N 120.333U 3.00N' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC UQQDWARD-CLYDE CONSULTANTS 30 OCT 80 PAGE 3 CAT. DATE TIME(GMT) LAT LONG SL INTEN MAG SM H DIS Q S L 0 C A T I 0 N AND C 0 M M E N T S NO. DAY-MO-YEAR HR-MIN-SEC (MM) (KM)(KM) ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE = 3.00 SCALE ='ML AUTHORITY** PAS 18 18 DEC 1934 05:28:00.0 34.583N 120.33314 3.00N' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE = 3,00 SCALE =ML AUTHORITY^ pAg 19 20 DEC 1934 12:37:00.0 34.583N 120.333U 2.SON' 16 P N HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED BY PASADENA QUALITC ORIGINAL DATA SOURCE = PAS LOCAL MAGNITUDE = 2.50 SCALE =ML AUTHORITY= PAS 20 20 DEC 1934 12:39:00.0 34.583N 120.33314 III 3.00N' 16 P N REPORTED FELT INFORMATION HYPOCENTER DEPTH ASSIGNED HYPOCENTER/EPICENTER DETERMINED