North America’s largest recorded earthquakes and largest documented volcanic eruptions both take place in southwest Alaska. A major shoreline-crossing community seismic experiment commenced in 2018, focused on the Alaska Peninsula subduction zone. Alaska is a GeoPRISMS primary site and current EarthScope target. The deployment is augmented by deployment of EarthScope Transportable Array (TA) seismic stations, earthquake and volcanic monitoring networks, and the recent development of a large pool of ocean bottom seismographs (OBSs). Together, these resource provide a unique opportunity to advance understanding of Alaska and subduction processes generally.
AACSE collects seismic data remotely onshore and offshore, all of which will be freely released to the community as rapidly as possible. The array includes 75 broadband OBSs and 30 land broadband sensors, recording for 15 months beginning May-June 2018. The array covers a broad area that spans the incoming plate, the megathrust and volcanic arc to the distal backarc, and includes a dense transect in the Kodiak/Katmai region. When integrated with the TA, the array extends 1500 km from incoming plate to the Arctic coast and spans 700 km along strike. The OBSs include 20 shielded sensors for deployment in shallow water. Many OBSs include absolute pressure gauges to capture possible slow slip events, while five OBSs and six land sites will include accelerometers to record large local earthquakes without clipping.
The AACSE broadband OBS deployment completed on July 20, teams of scientists deployed 75 instruments across two sailing legs aboard the R/V Sikuliaq. Twelve Apply-to-Sail participants and two K-12 teachers from Alaska participated in the deployment cruises by performing watchstanding duties, helping prepare instruments for deployment and maintaining the project blog.
The Sikuliaq runs multiple acoustic and oceanographic sensing systems while underway including: ocean current measurements (ADCP), seawater temperature, conductivity and density (CTD), echo sounder for fisheries research (EK60), multibeam bathymetry (32kHz Kongsberg EM302), parametric sub-bottom profiler for shallow subsurface imaging (Kongsberg TOPAS PS 18), R2R event logger, expendable bathythermograph for measuring water temperature (XBT). All data will be archived and available via the UNOLS R2R server. Additionally, multibeam data will be archived via the MGDS and sub-bottom data will be archived at the UTIG Academic Seismic Portal. For access to the data prior to archiving, contact the cruise co-chief scientists: Leg 1 – Lindsay Worthington (lworthington (at) unm.edu) and Leg 2 -Anne Sheehan (anne.sheehan (at) colorado.edu). Cruise reports available here: link to cruise report
The onshore broadband seismometers were deployed May-June 2018, with 29 stations installed on Kodiak, the Shumagin Islands, and the Alaska Peninsula. All stations include Nanometrics posthole PHQ-120 sensors recorded on Quanterra Q330 data loggers placed in low-profile aluminum boxes; the blog shows some photographs of installations. Six of those sites also record Titan accelerometers, all at 100 sps. The first data should be recovered during a service run in August-September 2018, and delivered to the IRIS DMC soon after. Keep an eye out for the first AACSE data!
A map of the current deployment plan and a detailed deployment plan can be found on the links below. The project is intended to help grow the seismological community, and includes opportunities to sail on OBS cruises and short courses for undergraduates – 2019 opportunities to be announced December 2018! Feel free to contact members of the PI team for more information.
Alaska Amphibious Community Seismic Experiment (AACSE)
icon-chevron-right Download the Deployment map (PDF, last update August 15, 2018)
Preliminary station locations
These locations are based on initial surveys only, and will be superseded by metadata generated when data are submitted to the IRIS DMC. They are provided for reference. Please use the metadata at the DMC for all analyses, once it is available. List of land stations, and of OBSs.
- All earthquake seismic data will be made available as it is retrieved and archived, through the IRIS DMC – OBS array has network code XD (2018-2019) and land array has network code XO (2018-2019).
- Underway marine data including multibeam bathymetry are being made available through MGDS and embedded into the GMRT grids, available through GeoMapApp and other interfaces. The deployment cruises are SKQ201811S and SKQ201816S.
- Sub-bottom TOPAS profiler data was collected on the Sikuliaq during both 2018 deployment cruises, and are being made available through the Academic Seismic Portal at UTIG.
icon-link Project web page: http://geoprisms.org/research/community-projects/alaska/
icon-chevron-right AACSE is deployed! The land array was deployed May-June 2018, and the OBSs finished deployment on July 20 2018.
icon-chevron-right The AACSE deployment has been funded and is scheduled for spring, 2018 deployment!
icon-chevron-right The AACSE plan will be presented and discussed at the September 2017 OBS Workshop in Portland, Maine!
icon-chevron-right The AACSE project team convened a GeoPRISMS MiniWorkshop just prior to the 2017 AGU in New Orleans
A webinar (April 25, 2016) introduced the community to the exciting scientific opportunities that this DCL offers and to outline general strategies for achieving them. Watch the record of the webinar below.
Presenters: Susan Schwartz, Geoff Abers, Emily Roland, Rob Evans, Doug Wiens, Jeff Freymueller
Deployment of the Alaska Amphibious Community Seismic Experiment (AACSE) kicks-off in May 2018. This major shoreline-crossing community experiment focuses on the subduction zone offshore the Alaska Peninsula, which has been the site of North America’s largest recorded earthquakes as well as major volcanic hazards.
Beginning in May 2018, 75 broadband ocean bottom seismometers (OBS) and 30 land stations will be deployed for the 15-month experiment. The array covers a broad area that spans the incoming plate, the megathrust and volcanic arc to the distal backarc, with a dense trench-normal transect in the Kodiak region.
Apply to Sail
Graduate students and scientists at all career stages are invited to sail with two OBS deployment legs of the AACSE during the late spring and early summer of 2018. The project will collect OBS data from offshore part of southern Alaska. Both legs of the deployment expedition will be aboard the Global-Class R/V Sikuliaq. The PI team anticipates that berths for 5 to 7 additional students or scientists will be available on each leg. Travel costs to Seward, AK will be paid for Apply to Sail participants, but no stipend is included.
Summer 2019 cruise dates are currently being finalized. Expect an announcement for opportunities in late 2018 or earliest 2019
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