Abstract
Within the Dead-Sea-Rift-Transect-(DESERT)-project seismic, seismological,
electromagnetic, gravity, magnetic, geodynamic and geological studies
were done at the Dead Sea Rift/Dead Sea Transform (DST) to give answers
to the question: How do shear zones work and what controls them?.
Most of the small scale experiments were located at the Araba fault,
which is the main fault of the DST-system between the Dead- and Red-Sea.
Seismic measurements in the Araba valley done by Maercklin 2003
provided a view of the p-wave velocity distribution of the subsurface
in the fault region. Haberland et al. 2003 performed a seismic
experiment at the Araba fault which showed the existence of guided
waves within a narrow channel of 3-12 m width. They correlated this
narrow vertical layer to the damage zone of the Araba fault. In March
2004 the Institute of Geophysics and Meteorology at the University
of Cologne investigated the near-surface conductivity structure of
the fault area with TEM measurements. These measurements were accomplished
with a new 3-component-TEM antenna attached to a three channel Nanotem
receiver. Using this setup, we were able to record horizontal and
vertical signals simultaneously. The design and construction of this
new 3-component TEM antenna was done at our institute in Cologne.
The transmitter signal was generated by a single turn 50m x 50m conductor-loop.
Preliminary results from these measurements are very interesting.
First, it seems that conductivity structures, we see in 1D-Inversions-results
of 1km Central-Loop profiles, correlate with velocity structures
derived by Maercklin 2004. Furthermore, our In-Loop measurements
seem to confirm the existence of a vertical near-surface conductivity-anomaly.
At our southernmost profile, this anomaly is located exactly at the
same position where the seismic-receivers of Haberland et al. 2003
recorded the biggest amplitude of the guided waves.
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