Current surface displacement along the Carmel Fault system in Israel from InSAR stacking and PSInSAR

Ran N. Nof, Gidon Baer, Yehuda Eyal, Fabrizio Novali

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

A long-standing dilemma in the geology of Israel is whether the Carmel Fault (CF), which splays off the Dead Sea Fault (DSF), is currently active. Unsolved issues include, among others, what is the slip rate along the fault, and to what extent does it contribute to the seismic hazard of the city of Haifa and the nearby petrochemical industry. While previous geologic and geomorphologic studies suggest vertical and/or left-lateral movements along the fault, paleoseismic studies along the fault did not find any evidence for surface rupturing during the last few 10K years. Recent GPS and precise-leveling campaigns showed somewhat controversial indications for vertical movements of the Carmel Mountain, with no clear implication to the CF. In this study we use Interferometric Synthetic Aperture Radar (InSAR) stacking and Permanent Scatterers in InSAR (PSInSAR) to measure the surface movements on both sides of the CF in an attempt to relate these movements to a possible slip along the fault. We processed a total of 45 ERS-1 and ERS-2 SAR images acquired between the years 1992 and 2001. Interferograms showed low signal-to-noise ratio (SNR), and no consistent (in places, even opposite) sense of apparent displacement in different interferograms. Positive and negative correlations with topography suggest that the major source of error is due to atmospheric stratification. Stacking interferograms improved the SNR, but uncertainties still remained high in the order of the signals. To further improve the results and remove the atmospheric contribution, PSInSAR analysis of 47 images was carried out. This analysis shows high sensitivity to local deformation features such as ground subsidence and compaction of soil, but no direct correlation was found between the PSInSAR results and seismicity or water level changes. PSInSAR analysis shows no evidence for relative slip along the CF. Using elastic dislocation modeling, we find that the lower detection limits on the NW-SE segments of the fault are 1 mm/year for vertical movement and 4 mm/year for horizontal sinistral movement. Thus, although unlikely, we cannot exclude creep along the Carmel Fault at rates lower than these limits.

Original languageEnglish
Pages (from-to)71-86 parent&backto=issue,1,5;journal,1,27;homemainpublications,2,5;
JournalIsrael Journal of Earth Sciences
Volume57
Issue number2
DOIs
StatePublished - 1 Dec 2008

ASJC Scopus subject areas

  • Earth and Planetary Sciences (all)

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