Active parasitic folds on the Elysian Park anticline: Implications for seismic hazard in central Los Angeles, California

TitleActive parasitic folds on the Elysian Park anticline: Implications for seismic hazard in central Los Angeles, California
Publication TypeJournal Article
Year of Publication2000
AuthorsOskin M, Sieh KE, Rockwell TK, Miller G, Guptill P, Curtis M, McArdle S, Elliot P
JournalGeological Society of America Bulletin
Volume112
Pagination693-707
Date PublishedMay
ISBN Number0016-7606
Accession NumberWOS:000086689400005
Abstract

We characterize the seismic hazard of the Elysian Park fault, a blind reverse fault beneath central Los Angeles, by analysis of the Elysian Park anticline, which overlies it, New shallow-subsurface geotechnical data, combined with other surficial stratigraphy and geomorphology, reveal that the Elysian Park anticline is an active 20-km-long structure. From the style and rates of deformation of parasitic folds on the southern limb of the anticline, we estimate a contraction rate of 0.6-1.1 mm/yr This rate provides a basis for estimating a rate of contraction of the entire Elysian Park anticline, which in turn allows us to estimate a 0.8-2.2 mm/yr time-averaged rate! of slip on the underlying fault. At this rate of slip, rupture of the Elysian Park fault could produce a nominal M-w 6.2 to 6.7 earthquake every 500 to 1300 gr, on average. Although this Elysian Park earthquake would recur infrequently, its size and recurrence interval may be similar to those estimated for the sources of the destructive 1971 San Fernando and 1994 Northridge earthquakes.