Crustal Structure Across the Central Dead Sea Transform and Surrounding Areas: Insights Into Tectonic Processes in Continental Transforms

• Published in: Tectonics (Washington, D.C.) D.C.), 2023-08, Vol.42 (8), p.n/a
• Main Authors: ten Brink, U. S., Levi, E., Flores, C. H., Koulakov, I., Bronshtein, N., Ben‐Avraham, Z.
• Format: Article
• Language: English
• Subjects: Continental margins; Crustal structure; Deformation; Earthquakes; Fault lines; Faults; Geographical distribution; Geological structures; Geological time; Geophysical exploration; gravity modeling; Lakes; Lithosphere; Modelling; Moho; Moho step; Movement; Plate motion; Plate tectonics; Plates; pull‐apart basin; Sea of Galilee; Seismic activity; seismic refraction; Seismicity; Shape; shoulder uplift; Tectonic processes; Temporal variations
• ISSN: 0278-7407; 1944-9194
• DOI: 10.1029/2023TC007799

New geophysical profiles across the central Dead Sea Transform (DST) near the Sea of Galilee, Israel, and surrounding highlands, augmented by static stress modeling, allow us to study continental transform plate deformation. The DST separates a ∼10 km thick sedimentary column above a thinned (16–23 km) crust to the west from a ∼7 km column above a ∼30‐km thick crust to the east. Crustal thinning starts under the DST, as observed also farther south, indicating that the DST is indeed located along the boundary between the Arabian plate and its continental margin. Moho step here is gradual. The DST's eastern shoulder dips westward toward the DST unlike the upward flexed shoulder observed farther south, perhaps delineating the northern limit of a thinner and hotter lithosphere. The shape of the Sea of Galilee is modeled as an asymmetric pull‐apart basin formed by a left‐lateral stepover of 2.6 km between slightly divergent and underlapping strike‐slip fault strands dipping 70° to the west. Reflection data indicate that these strands are not connected. Several fault traces within the Sea of Galilee have previously been suggested to carry part of the relative plate motion. However, given slip along the main DST faults, Coulomb stress will increase only on fault portions in the northern part of the lake, in accord with the geographical distribution of seismicity, suggesting that these faults are likely secondary. Mismatch between the DST strand locations in the geophysical profiles and the subsidence model, may reflect temporal changes in fault geometry. Plain Language Summary The Dead Sea fault system is a vertical discontinuity in the Earth upper layers, where two tectonic plates move laterally relative to each other. Their relative motion produce earthquakes and control the surface topography and sub‐surface structure. We imaged by geophysical methods the subsurface structure of this fault system and its surrounding region at the northern end of the Sea of Galilee, Israel, and we modeled the shape of the lake and the seismic rupture potential of faults there. The two plates, separated by the Dead Sea fault system, are the interior Arabian plate and its former margin, created during the formation of the Eastern Mediterranean Sea. As expected, the geological structure is different on either side of the fault system. The shape of the lake and recent seismicity in the area can be explained by lateral plate motion centered on two major faults with an intervening ga