HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) References Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sowers, J. M. Articles by Rubin, T. D. Search for Related Content GeoRef GeoRef Citation

Relationship of the kickapoo fault to the Johnson Valley and Homestead Valley faults, San Bernardino County, California

William Lettis & Associates, Inc., Oakland, California 94607-4041

Abstract

The 1992 M_w 7.3 Landers earthquake rupture propagated from the Johnson Valley fault to the Homestead Valley fault across Homestead Valley. Rupture was concentrated along the Kickapoo fault (a.k.a, Landers fault), a previously unrecognized north-south-striking, 5-km-long fault in Homestead Valley, and along small secondary fault traces east of the Kickapoo fault. To better understand the role of the Kickapoo fault in accommodating slip between the Johnson Valley fault and the Homestead Valley fault, we performed detailed aerial photograph interpretation and field mapping of alluvial deposits, geomorphology, and co-seismic surface rupture; evaluated existing water-well data; and conducted a gravity survey of the Homestead Valley area. These data show that the Kickapoo fault is a pre-1992 structure best interpreted as the northward continuation of the southern Johnson Valley fault. The Kickapoo fault merges northward with the northwest-striking Homestead Valley fault. Thus, we interpret that the Johnson Valley, Kickapoo, and Homestead Valley faults form an interlinked system. Large ruptures similar to the 1992 Landers rupture may have repeatedly propagated between the Johnson Valley and Homestead Valley faults along the Kickapoo fault. The Kickapoo-Johnson Valley fault intersection defines a 1-km-wide, left-restraining bend. Uplifted alluvial deposits and pressure ridges are common within the bend, indicating the bend is a long-lived contractional feature. Homestead Valley itself is underlain by relatively thin alluvial deposits over crystalline bedrock, showing that no significant subsidence has occurred during the late Quaternary. These observations are consistent with the accommodation of north-south right shear on the southern Johnson Valley and Kickapoo faults in Homestead Valley.

This article has been cited by other articles:

				P. Mann Global catalogue, classification and tectonic origins of restraining- and releasing bends on active and ancient strike-slip fault systems Geological Society, London, Special Publications, January 1, 2007; 290(1): 13 - 142. [Abstract] [Full Text] [PDF]

				W. H. Bakun Estimating Locations and Magnitudes of Earthquakes in Southern California from Modified Mercalli Intensities Bulletin of the Seismological Society of America, August 1, 2006; 96(4A): 1278 - 1295. [Abstract] [Full Text] [PDF]

				B. T. Aagaard, G. Anderson, and K. W. Hudnut Dynamic Rupture Modeling of the Transition from Thrust to Strike-Slip Motion in the 2002 Denali Fault Earthquake, Alaska Bulletin of the Seismological Society of America, December 1, 2004; 94(6B): S190 - S201. [Abstract] [Full Text] [PDF]

				Interactions between the Landers and Hector Mine, California, Earthquakes from Space Geodesy, Boundary Element Modeling, and Time-Dependent Friction Bulletin of the Seismological Society of America, May 1, 2002; 92(4): 1450 - 1469.

				Relationship of the 1999 Hector Mine and 1992 Landers Fault Ruptures to Offsets on Neogene Faults and Distribution of Late Cenozoic Basins in the Eastern California Shear Zone Bulletin of the Seismological Society of America, May 1, 2002; 92(4): 1592 - 1605.

				Influence of Releasing Step-Overs on Surface Fault Rupture and Fault Segmentation: Examples from the 17 August 1999 Izmit Earthquake on the North Anatolian Fault, Turkey Bulletin of the Seismological Society of America, February 1, 2002; 92(1): 19 - 42.

				The 1999 Izmit, Turkey, Earthquake: A 3D Dynamic Stress Transfer Model of Intraearthquake Triggering Bulletin of the Seismological Society of America, February 1, 2002; 92(1): 245 - 255.

				Paleoseismology of the Johnson Valley, Kickapoo, and Homestead Valley Faults: Clustering of Earthquakes in the Eastern California Shear Zone Bulletin of the Seismological Society of America, October 1, 2000; 90(5): 1200 - 1236.

				M. A. Hemphill-Haley and R. J. Weldon II Estimating prehistoric earthquake magnitude from point measurements of surface rupture Bulletin of the Seismological Society of America, October 1, 1999; 89(5): 1264 - 1279. [Abstract] [PDF]

				L. E. Jones and D. V. Helmberger Earthquake source parameters and fault kinematics in the eastern California shear zone Bulletin of the Seismological Society of America, December 1, 1998; 88(6): 1337 - 1352. [Abstract] [PDF]

				J. R. Unruh, W. R. Lettis, and J. M. Sowers Kinematic interpretation of the 1992 Landers earthquake Bulletin of the Seismological Society of America, June 1, 1994; 84(3): 537 - 546. [Abstract] [PDF]