High-resolution stratigraphy reveals repeated earthquake faulting in the Masada Fault Zone, Dead Sea Transform

A detailed study of the syndepositional Masada Fault Zone (MFZ) provides an example for fundamental characteristics of earthquakes, such as long term temporal clustering, repeated faulting on the same planes for a limited time of the order of a few thousands of years, and the formation of subaqueous breccia layers interpreted as seismites. The MFZ was studied in outcrops of 70-15 ka Lake Lisan sediments. Detailed columnar sections on both sides of well-exposed faults show that each individual fault exhibits a cluster, up to 4 ky long, with 3-5 slip events on the same plane. Each slip event is associated with the formation of widespread layers exhibiting soft sediment deformation, which are interpreted to be seismite layers. The uppermost part of the Lisan section, about 5 m, is not faulted, hence the last cluster of slip events ended about 25 ky ago. The clusters of activity of individual faults coalesce to form larger clusters. These are evident in the distribution of seismite layers throughout the entire Lisan section which shows earthquake clustering during periods of similar to 10 ky. The clusters are separated by relatively quiescent periods of comparable duration. (c) 2005 Elsevier B.V. All rights reserved.