USGS SCIENTISTS RESPOND TO SAG,S REQUEST FOR

UNCLAS JEDDAH 000261

SIPDIS

DEPT FOR NEA/ARP, DEPT OF THE INTERIOR FOR USGS/VDAP

E.O. 12958: N/A
TAGS: AEMR ASEC CASC PGOV SA
SUBJECT: USGS SCIENTISTS RESPOND TO SAG,S REQUEST FOR
ASSISTANCE

REF: JEDDAH 190


1. (U) SUMMARY: On June 12 the USGS Volcano Assistance
Program responded to the Saudi Geological Survey,s request
for assistance (reftel) by deploying two scientists to the
Kingdom on June 12. While in country VDAP worked with SGS in
the lab and field to assess signals of an impending eruption
and to develop a volcano and volcanic earthquake warning
system. END SUMMARY


2. (U) BACKGROUND: The Harra Lunayyir area known as Harra
Shagah locally in north western Saudi Arabia has experienced
increased seismic activity and ground deformation during the
past two years. This increase in activity began with a swarm
of tens of thousands of micro earthquakes in February 2007
and continued with two additional waves with as many as
20,000 additional earthquakes in April and May 2009. On April
17, following an increase in earthquake magnitude to
magnitude 4.8 and discovery of ground cracks in the
northeastern region of Harra, SGS advised Civil Defense
authorities of the possibility of larger damaging earthquakes
and/or volcanic eruption. As a result of these SGS warnings,
the Saudi Arabian Civil Defense authority evacuated the
population within 20 Km of the earthquake epicentral area.



3. (U) MAGMATIC INTRUSION MAY HAVE CAUSED QUAKES: John
Pallister and Wendy McCausland of the USGS Volcano
Assistance Program (VDAP) arrived in the Kingdom on June 12
in order to help SGS scientists assess the volcanic risk and
provide advanced techniques for volcanic monitoring, eruption
forecasting as well as volcano and seismic hazard assessment.
After running several tests and collecting data, the two
scientists report that they are convinced that magmatic
intrusion is the source of the earthquakes due to several
evident hallmarks of volcanic activity, including distinctive
volcanic types of earthquakes and signs of uplift on remotely
sensed data. The two also noted that gas emissions would also
be expected with this type of intrusive magmatic activity,
although none has been detected thus far. They believe this
may be because the gas has diffused and is therefore
difficult to detect. SAG,s principle concern remains that of
additional earthquakes. Based on existing evidence, VDAP has
reassured SGS that large earthquakes (greater than M5.5 or
M6) are unlikely in this situation.


4. (U) NEXT STEPS: USGS assisted SGS in writing a 60 page
scientific and hazard report that will be published in the
near future. USGS scientists also report that SGS has shown a
strong interest in pursuing a long-term relationship with the
organization, something that USGS is considering
internally.


5. (U) COMMENT: Post will continue to monitor the earthquake
situation in the northwest part of the country and report on
any substantive updates.
TONEY