Seismic field work focused on the installation of 14 new seismic monitoring stations. Several AEIC personnel spent the month of July working with Gary Pavlis and two students from Indiana University to install stations in the park. The combined teams succeeded in installing two VSAT satellite telemetry sites to relay data from 14 new seismic stations throughout the Chugach and St. Elias mountain ranges.

This was the second field season of seismic station installations for the STEEP project and it brings the total number of new monitoring sites to 22, arrayed between Malaspina Glacier in the southeast and McCarthy in the northwest. These sites will provide important data for current efforts to understand the active mountain building processes in the Chugach-St. Elias ranges and they will also become part AEIC's permanent statewide network of earthquake monitoring stations.

STEEP (SainT Elias Erosion/tectonics Project) is a five year, multi-disciplinary study that addresses evolution of the highest coastal mountain range on Earth - the St. Elias Mountains of southern Alaska and northwestern Canada. The overall goal of the project is to develop a comprehensive model for the St. Elias orogen that accounts for the interaction of regional plate tectonic processes, structural development, and rapid erosion. The seismic component of this project includes a passive seismic experiment utilizing the IRIS PASSCAL Program instruments. A total of 22 new, broadband, seismic stations have been installed in the St. Elias region. All use Freewave IP radios to provide telemetry to a DSL, a DDS or one of three VSAT,connections that provide continuous data transmission to Fairbanks. The data are also recorded local disk storage using Quanterra packet balers. The telemetry data are recorded in real time and used in standard data processing at the Alaska Earthquake Information Center. The network is proving clear improvements in detection and location capabilities for events in the St. Elias region. Processing of teleseismic data is ongoing for estimates of crustal thickness using receiver functions and mantle anisotropy with shear wave splitting. Since the beginning the new STEEP network installations in July, 2005, the AEIC has located over 400 events in the area, the largest having a magnitude of 3.9. Majority of the events have shallow crustal depths. The deepest events (down to 64 km) are located in the northwestern part of the project area near Wrangell volcanoes. The newly recorded earthquakes follow the pattern of the long term seismicity trend. They mostly cluster in the Icy Bay-Yakutat Bay area, along the central part of the Chugach-St.Elias fault system, and near the Duke River fault. A number of glacial quakes have also been located with the newly installed network. These events primarily concentrate in the Icy Bay area.

Map of STEEP Seismic Sites.

Record section of M3.9 earthquake that occurred on September 22, 2006.