The Alaska Earthquake Information Center (AEIC) located a total of 10,564 earthquakes in Alaska between April 1st and September 30th. Of these, 35 were felt. There were 16 events greater than or equal to magnitude 5.0, and 97 events between magnitude 4.0 and 4.9. The largest event during this period was a magnitude 6.6 (ml) 58 miles SE of Amchitka on August 2nd. Detailed seismicity reports are available online at: AEIC Seismicity Reports.
In July, Seismologist Dr. Natasha Ruppert and Tsunami Modeler Elena
Suleimani attended the XXIV
IUGG Assembly (International Union of Geodosy and Geophysics) in
Perugia, Italy. Suleimani participated in the Tsunami Symposium and
gave a presentation on the progress of
Tsunami Inundation Mapping
for Alaska. Dr. Ruppert gave a presentation on analysis of aftershock
data from the 2002
Denali Fault earthquake sequence.
In September, AEIC and the Geophysical Institute hosted a regular
meeting of the
Alaska Seismic Hazards Safety Commission. Seismologists and staff
from AEIC spoke to the ASHSC commissioners about AEIC operations, tsunami
inundation mapping, the Denali Fault earthquake sequence, implementation
of ShakeMap
for Alaska, and the development of real time earthquake information
displays for Alaska's local emergency operations centers.
Implementation of a Summary Database - Significant improvements in the
efficiency of data flow and the redundancy & stability of AEIC's earthquake
monitoring systems have been achieved with the creation of a Summary
Database for earthquake event information. The new database consolidates
earthquake solutions that had previously been archived in a number of
separate databases. The summary database contains AEIC's automatic
earthquake solutions as well as earthquake location data from the
National Earthquake Information Center
and the West Coast/Alaska Tsunami Warning Center.
The summary database will make important real time earthquake information
more easily available to AEIC duty seismologists. It will also provide
a better framework for developing software and systems that rely on up
to the minute earthquake data, such as ShakeMap, displays for local
emergency management centers, routine processing of seismic data,
and the Recent EQ's
portion of the AEIC website.
On May 1st, the helicorders (also known as paper drum recorders, or seismographs)
operated in the Seismology Lab by the Alaska
Volcano Observatory were shut down permanently. This event marked the end of
an era in which analog recordings of earthquake signals on paper were an important
tool for monitoring seismic activity. AVO is in the process of replacing the
helicorders with onscreen, digital displays of earthquake signals from the 33
active volcanoes that are monitored in Alaska.
New seismic monitoring stations were installed in several locations within Alaska
during the summer field season. With support from the
Alaska Division of Geological and Geophysical Surveys, AEIC installed
two stations along the Alaska Highway to gather seismic data for geologic
mapping and hazards assessment project along a proposed natural gas pipeline corridor.
The new stations are located at Independence Ridge and Sand Creek between Delta Junction
and Tok. AEIC Field Technician John Sandru installed the stations in July with
assistance from seasonal Field Technician Morgan Fowler. Another important new
seismic monitoring station was installed on Sitkinak Island in August by AEIC Field
Technician Martin La Fevers.
Maintenance of existing seismic monitoring stations in the statewide AEIC network
was carried out by La Fevers, Sandru, and Seismic Network Engineer Steve Estes
throughout the summer. Important stations at Sawmill Creek and Paxson were repaired
by Estes following damage by lightning strikes. The seismic station and
VSAT
telemetry site at Bering Glacier Camp received a critical power system upgrade
that will keep the site operational throughout the winter so that seismic data
from a number of stations in the STEEP
project network can be received in Fairbanks.
A network of temporary seismometers was installed in Denali National Park and
Preserve by Seismologist Dr. Natasha Ruppert and Field Technician John Sandru
with support from the National Park Service. The stations, located between Mt.
McKinley and Kantishna, were operated throughout the summer to collect seismic
data for the study of an anomalous zone of frequent, shallow earthquakes know
as the Kantishna Cluster.
A number of new stations also came on line at pump stations along the Trans-Alaska
Pipeline as part of an ongoing project to monitor earthquake activity for Alyeska
Pipeline Service Company. Field Technician John Sandru installed seismometers
at pump stations 6 through 12 from the Yukon River south to Valdez. Installation
of the pipeline seismic monitoring stations will continue in 2007 and 2008 with new
seismometers at pump stations in the northern half of Alaska.
AEIC welcomed the arrival of GIS Specialist Dave West during the summer. West assumed the position of Tsunami GIS Coordinator working with Elena Suleimani on AEIC's Tsunami Inundation Mapping project. West will be compiling spatial data for tsunami inundation mapping as well as providing general GIS services for the Seismology Lab.
Public tours of the seismology lab (AEIC & AVO) were conducted each Wednesday
afternoon between June 1st and August 31st.
AEIC's "Earthquake Booth" was once again a success at the Tanana Valley State
Fair in early August. In what is easily the most significant public outreach
conducted each by AEIC each year, faculty, staff, and students met with hundreds
of members of the public to provide earthquake information, answer questions,
and demonstrate how earthquakes happen with the venerable earthquake machine.
In September, AEIC Data Analyst Jamie Roush traveled to the communities of
King Cove, Cold Bay, and Sand Point to raise awareness of tsunami and earthquake
hazards in coastal regions of Alaska. In support of the West Coast/Alaska
Tsunami Warning Center's Tsunami
Ready program, Roush and colleagues from WC/ATWC, the Alaska Division of Homeland
Security and Emergency Management, and the National Weather Service gave lectures
in local schools and at public forums to raise awareness of seismic hazards
and to improve disaster preparedness.