Abstract. Instrumental strong motion data are not common around the Dead
Sea region. Therefore, calibrating a new attenuation equation is a
considerable challenge. However, the Holy Land has a remarkable historical
archive, attesting to numerous regional and local earthquakes. Combining the
historical record with new seismic measurements will improve the regional
equation. On 11 July 1927, a rupture, in the crust in proximity to the northern Dead
Sea, generated a moderate 6.2 ML earthquake. Up to 500 people
were killed, and extensive destruction was recorded, even as far as 150 km
from the focus. We consider local near-surface properties, in
particular, the shear-wave velocity, as an amplification factor. Where the
shear-wave velocity is low, the seismic intensity far from the focus would
likely be greater than expected from a standard attenuation curve. In this
work, we used the multichannel analysis of surface waves (MASW) method to
estimate seismic wave velocity at anomalous sites in Israel in order to
calibrate a new attenuation equation for the Dead Sea region. Our new attenuation equation contains a term which quantifies only
lithological effects, while factors such as building quality, foundation
depth, topography, earthquake directivity, type of fault, etc. remain out
of our scope. Nonetheless, about 60 % of the measured anomalous sites fit
expectations; therefore, this new ground-motion prediction
equation (GMPE) is statistically better than the old
ones. From our local point of view, this is the first time that integration of the
1927 historical data and modern shear-wave velocity profile measurements
improved the attenuation equation (sometimes referred to as the attenuation
relation) for the Dead Sea region. In the wider context, regions of
low-to-moderate seismicity should use macroseismic earthquake data, together
with modern measurements, in order to better estimate the peak ground
acceleration or the seismic intensities to be caused by future earthquakes.
This integration will conceivably lead to a better mitigation of damage from
future earthquakes and should improve maps of seismic hazard.
Three-dimensional shear wave velocity imaging by ambient seismic noise tomography