Abstract
The Dead Sea Transform (DST) dominates the seismicity of Israel,
Palestinian Authority, Lebanon and Syria. It is a deep (down to -430
MSL) and narrow (8 to 20 km) morpho-tectonic trough, with a total length
of 1100 km. 105 km of left-lateral motion combined with deep sediment
filled depressions result in short-wavelength heterogeneity of the upper
crust.
With displacement rate of < 5 mm/y, the seismicity of the DST is
relatively low, resulting in a limited catalog of recorded strong
motions.The regional pre-instrumental catalog (> 3000 years),
however, contains numerous M > 7. The lack of recorded strong ground
motions in Israel results in a critical knowledge gap regarding the
distribution of seismic energy throughout the region. This criticality
is further amplified given a slip deficit on major segments (equivalent
to M > 7) and the proximity of potential sources (< 60 km) to
areas of critical infrastructures and urban centers.
In this research, we study the influence of the DST crustal
heterogeneities on ground motions in northern Israel. The combination of
deep sedimentary basins, up to 7 km deep, bounded by active faults is
unique and requires in-depth investigation of the impact of this
specific setting on the partition of seismic energy in the region.
To this end, we have developed an idealized 3-D regional model which
includes the DST trough and the north-west branching Carmel Fault Zone
(CFZ). The model is based on up-to-date structural data and deep
boreholes, includes all the major basins along the DST and the CFZ. The
model also includes the Zevulun sedimentary basin, which underlies the
Haifa bay area, where dense population and major petrochemical
installations are found in proximity.
We modeled earthquake scenarios using a kinematic finite fault source
and propagated the wave field using the SW4 software. We show that
regional energy partition depends on the exact source location along the
DST trough, changing from waveguide to resonant box. Concerning the
Haifa bay, we show that for similar epicentral distance (55 to 58 km)
the amplitude of ground motions is determined by the location of the
source along the DST, changing the PGV by a factor 3.This research shows
the importance of 3-D numerical models, specifically their ability to
address the three components of ground motion convolution: source, path,
and site.
Original language | English |
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Title of host publication | American Geophysical Union, Fall Meeting 2019 |
Volume | 33 |
State | Published - 1 Dec 2019 |
Keywords
- 7209 Earthquake dynamics
- SEISMOLOGY
- 7212 Earthquake ground motions and engineering seismology
- 7215 Earthquake source observations
- 7290 Computational seismology