Characterizing a large shear‐zone with seismic and magnetotelluric methods: The case of the Dead Sea Transform

Abstract

Seismic tomography, imaging of seismic scatterers, and magnetotelluric soundings reveal a sharp lithologic contrast along a ∼10 km long segment of the Arava Fault (AF), a prominent fault of the southern Dead Sea Transform (DST) in the Middle East. Low seismic velocities and resistivities occur on its western side and higher values east of it, and the boundary between the two units coincides partly with a seismic scattering image. At 1–4 km depth the boundary is offset to the east of the AF surface trace, suggesting that at least two fault strands exist, and that slip occurred on multiple strands throughout the margin's history. A westward fault jump, possibly associated with straightening of a fault bend, explains both our observations and the narrow fault zone observed by others.

Combining satellite and seismic images to analyse the shallow structure of the Dead Sea Transform near the DESERT transect

“…Approximately 1 km to the E of the AF, a relatively transparent zone might point to a second segment of the AF. This proposed segment, 1 km E of the AF, is not visible at the surface, but has been detected at depth in scattered seismic waves down to a depth of 4 km (Maercklin et al 2004) and also in the joint interpretation of seismic waves with magnetotellurics (Ritter et al 2003, Maercklin et al 2005, Bedrosian et al 2007). See also Ryberg et al (2007), for the vicinity of profile km 57 at Fig.…”

“…DESERT , Maercklin et al (2004Maercklin et al ( , 2005, Mechie et al (2005, Mohsen et al (2005), Koulakov and Sobolev (2005), Ritter et al (2003), Gö tze et al (2006, Janssen et al (2004Janssen et al ( , 2005Janssen et al ( , 2007, Sobolev et al (2005), Fö rster et al (2007, and Petrunin and Sobolev (2006). Key questions addressed here are: (1) What is the shallow structure of the southern DST?…”

Shallow architecture of the Wadi Araba fault (Dead Sea Transform) from high-resolution seismic investigations

“…Furthermore, on some sections energy presumably related to very-near-surface structures beneath the sources and/or receivers and arriving after the first breaks (site effects) might also be contained in the stacked data (see also Maercklin et al, 2005).…”

“…For the migration the smoothed velocity models from the first-break tomography for the shallow parts were used, for the deeper parts we resort to the velocity model by Maercklin et al (2005). Figure 8 gives the migrated sections.…”

“…Seismological investigation (Rümpker et al, 2003) and refraction, reflection seismic investigations and receiver function studies (DESERT Team, 2004;Mohsen et al, 2005;Mechie et al, 2005) revealed the transform structure at the crustal scale. With seismic scattering analysis and the combination of seismic tomography and magnetotelluric investigations (Ritter et al, 2003;Maercklin et al, 2005) the upper crustal seismic structure in the direct vicinity of the Wadi Araba Fault (WAF), the principal fault strand of the DST, was studied down to 4 km depth. A study of guided waves furthermore detected a waveguide presumably related to the WAF (Haberland et al, 2003).…”