Neotectonics of the Sea of Galilee (northeast Israel): implication for geodynamics and seismicity along the Dead Sea Fault system

Luca Gasperini,Marco Ligi,Christian Hensen,Matteo Lupi,Antonio Caracausi,Mark Schmidt,Alina Polonia,Adriano Mazzini,Michael Lazar,Antoine Haddad

doi:10.1038/s41598-020-67930-6

Abstract

The Sea of Galilee in northeast Israel is a freshwater lake filling a morphological depression along the Dead Sea Fault. It is located in a tectonically complex area, where a N-S main fault system intersects secondary fault patterns non-univocally interpreted by previous reconstructions. A set of multiscale geophysical, geochemical and seismological data, reprocessed or newly collected, was analysed to unravel the interplay between shallow tectonic deformations and geodynamic processes. The result is a neotectonic map highlighting major seismogenic faults in a key region at the boundary between the Africa/Sinai and Arabian plates. Most active seismogenic displacement occurs along NNW-SSE oriented transtensional faults. This results in a left-lateral bifurcation of the Dead Sea Fault forming a rhomb-shaped depression we named the Capharnaum Trough, located off-track relative to the alleged principal deformation zone. Low-magnitude (ML = 3–4) epicentres accurately located during a recent seismic sequence are aligned along this feature, whose activity, depth and regional importance is supported by geophysical and geochemical evidence. This case study, involving a multiscale/multidisciplinary approach, may serve as a reference for similar geodynamic settings in the world, where unravelling geometric and kinematic complexities is challenging but fundamental for reliable earthquake hazard assessments.

Highlights

Geological setting.The SoG or Lake Kinneret (Kinnor = harp in Hebrew) in northeast Israel, is a freshwater lake with a maximum extent of 12 × 20 km in the E-W and N-S directions, respectively
The present work is based on processing and interpretation of waterborne geophysical data collected during a recent (2017) campaign, integrated with reprocessed available datasets and coupled with geochemical and seismological observations carried out in the SoG and its surroundings
Single-beam bathymetries were used by Guitton and Claerbout[63] to test algorithms for filtering non-Gaussian noise in the form of spikes inside the lake and at the track ends

Summary

Introduction

The SoG basin is one of a series of rhomb-shaped grabens developing along the DSF s ystem[3], a continental transform fault displacing laterally the Africa/Sinai and Arabian plates at a rate of about 4.5 mm/year (Fig. 1). Tectonic deformations in this region are mainly oriented N-S, except for the CarmelGilboa fault (CG) oriented SE-NW, and a major eastward bending of the DSF main track towards Lebanon (LBR), to the south and north of the SoG, respectively (Fig. 1). Additional indirect evidence for active tectonics was inferred by earthquake surface ruptures detected in the vicinity of the S oG10,11 as well as by the high heat-flow measurements[12]

Methods

Results

Conclusion