The Arava Valley section of the Dead Sea Transform (DST) in southern Israel is characterized by the absence of seismic activity in recent times. However, paleoseismic analysis of sediments in the Avrona Playa, a pull-apart basin along the DST, reveals that at least six M > 6 tectonic events have affected the Avrona playa in the last 14,000 yr. The recurrence interval of the events is approximately 2000 yr. Trenched normal faults and push-up ridges in the playa show that the upper 2 m of the deformed sedimentary sequence consists of playa deposits with uniform soil development. The deformed sediments and the soil are typical of basins with an endoreic fluvial system. Based on the limiting age of the sequence and the extent of soil development, faulting in the playa, followed by compression and uplift, occurred in the last 1000 yr. This most recent tectonic event displaced the surface by at least 1 m, consistent with a M > 6.5 earthquake. This earthquake changed the morphology of the Avrona Playa from a closed system with internal drainage to an open basin, resulting in relief inversion. The seismic quiescence in the Arava may indicate a seismic gap in this segment of the DST.
Bibliographical noteFunding Information:
This work was made possible through the financial support of the Earth Science Research Administration of Israel. The authors thank H. Wust for fruitful discussions, Mr. G. Rosenbaum, Mrs. D. Stiber, and Mr. A. Barzilay for the laboratory analyses, and Mrs. Bat-Sheva Cohen and Mrs. Nehama Shragai for drawing the figures. We thank Ximena Barrientos for editorial assistance. Grateful acknowledgments are extended to James Dolan and an anonymous reviewer for their constructive comments. We especially thank the technicians of the GSI whose encouragement and unlimited help under difficult field conditions contributed to the success of this study.
- Alluvial fans
- Dead Sea Rift
- Holocene faulting