NEWS
Important Update: LDEO OBS station locations incorrect in channel metadata
Prior to late June, 2020, station locations were incorrectly reported in some metadata for LDEO OBS sites (station codes LA##, LD##, and LT##). Specifically, metadata requested from the IRIS DMC at the level of “channel” reported latitude, longitude, and elevation from planning documents, and not from final surveyed OBS locations, while metadata requested at the level of “station” correctly reported final OBS locations. Users should compare station location information for all data downloaded prior to late June, 2020 to correct locations stored in station-level metadata or to correct final locations reported in the table (.txt or .xls) to ensure that correct station locations were used. New metadata were submitted for LDEO OBS sites on June 26, 2020, and should be available shortly after this date.
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The Alaska Amphibious seismic data are now available
We are happy to announce the release of seismic data from the Alaska Amphibious Community Seismic Experiment (AACSE). This community experiment includes 75 ocean-bottom seismometers and 30 onshore broadband seismographs, deployed across and seaward of the Alaska Peninsula, for 15 months in 2018-2019. Along with the broadband array, a 400-element 3-component nodal array was deployed for one month cross Kodiak, air guns shot into the broadband and nodal arrays in 2019, and extensive multibeam and sub-bottom profile data were collected offshore.
All broadband seismometer data are now available from the IRIS Data Center under network code XO, and the nodal data are available under network code 8J. Marine geophysical data are available or being made available through the Marine Geoscience Data System.
In addition, the creation of a seismicity catalog is underway, led by the Alaska Earthquake Center and the AACSE PI group. This catalog is being constructed using the same methods as used to produce the routine AEC seismicity catalog, and will be released via the same mechanisms. It is anticipated that this catalog will be released some time mid-late 2020. In parallel, an effort is underway to estimate and archive OBS instrument orientations.
Details of the project are described below and in a recent Eos article (Abers et al., 2019, EOS 100(10), p. 30-35, ). The “Deployment and Data” tab provides links to several individual datasets.
Sincerely,
The AACSE PI Team (Geoff Abers, Aubreya Adams, Anne Becel, Peter Haeussler, Emily Roland, Susan Schwartz, Anne Sheehan, Donna Shillington, Spahr Webb, Doug Wiens, Lindsay Worthington)
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The cruise reports are now available
It’s a wrap! With the very last OBS recovered, the AACSE is now completed. Read the final blog
Aleutian – Alaska GeoPRISMS Synthesis Workshop | Lamont, August 5 & 6, 2019
The workshop gathered participants – many were students and postdocs – involved with NSF GeoPPRISMS projects aimed at the Alaska-Aleutians subduction zone, to engage in interdisciplinary discussions that lead toward synthesizing research results. All approaches were welcomed including geophysics, geology, geochemistry and geodynamics. The workshop included a mix of talks, posters, discussion sessions and meals to network and work toward GeoPRISMS science goals.
Aleutian Alaska Workshop participants during dinner at LDEO – August 5-6, 2019. Photo by T Plank
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In June 2019, seven undergraduate students, selected from a national pool of 54 applicants, participated in an AACSE short course in Kodiak, AK, led by PI Aubreya Adams (Colgate University). During the week-long experience, participants were first immersed in a short but intensive course introducing topics in seismology, plate tectonics, and the tectonic history of Alaska. A fieldtrip led by Peter Haeussler (USGS) and Gary Carver (Humboldt State University) introduced students to the geology of accretionary prisms. Finally, the group joined PI Lindsay Worthington (UNM) in the recovery of 398 nodes in eastern Kodiak. To summarize and share their newfound knowledge and experience with others, students from the course built a story map, highlighting the history and goals of the AACSE as well as their own experiences in Kodiak.
About AACSE
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.
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 onshore data were recovered during a service run in August-September 2018, and are NOW AVAILABLE at the IRIS DMC, network code XO. OBS data will be available after recovery in 2019.
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 in December 2018! Feel free to contact members of the PI team for more information.
The cruise reports are now available. MGDS is the primary repository. Please find below links to PDF report for each cruise and their MGDS webpage.
Alaska Amphibious Community Seismic Experiment Leg 1 Deployment | SKQ201811S R/V Sikuliaq
09 May 2018 – 29 May 2018
Seward, AK, USA to Seward, AK, USA
More information
Alaska Amphibious Community Seismic Experiment Leg 2 Deployment | SKQ201816S R/V Sikuliaq
July 11 – 25, 2018
Seward, AK, USA to Seward, AK, USA
More information
Alaska Amphibious Community Seismic Experiment Active source survey component | MGL1903 R/V Marcus G. Langseth
June 7 – June 24, 2019
Kodiak, AK to Kodiak, AK, USA
More information
Alaska Amphibious Community Seismic Experiment Recovery Leg 1 | SKQ201918S R/V Sikuliaq
10 August 2019 – 29 August 2019
Seward, AK, USA to Kodiak, AK, USA
More information
Alaska Amphibious Community Seismic Experiment Leg 2 Recovery: WHOI OBSs and multibeam surveying | MGL1907 R/V Marcus G. Langseth
27 August 2019 – 12 September 2019
Kodiak, AK, USA to Kodiak, AK, USA
More information
Underway Data from June 2019 active-source cruise
Alaska Amphibious Community Seismic Experiment (AACSE)
Download the Deployment map (PDF, last update September 18, 2018)
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.
Data Availability
Final station locations based on OBS acoustic surveys or GPS position onshore are available from the IRIS DMC’s Station metadata, or on this table (.txt or .xls).
All broadband seismometer data are now available from the IRIS Data Center under network code XO, and the nodal data are available under network code 8J. Marine geophysical data are available or being made available through the Marine Geoscience Data System.
In addition, the creation of a seismicity catalog is underway, led by the Alaska Earthquake Center and the AACSE PI group. This catalog is being constructed using the same methods as used to produce the routine AEC seismicity catalog, and will be released via the same mechanisms. It is anticipated that this catalog will be released some time mid-late 2020. In parallel, an effort is underway to estimate and archive OBS instrument orientations.
Project web page: http://geoprisms.org/research/community-projects/alaska/
The AACSE PI Team at the Portland (ME) OBS Workshop in September 2017. From left to right, top to bottom: Lindsay Worthington, Susan Schwartz, Anne Sheehan, Spahr Webb, Emily Roland, Donna Shillington, Aubreya Adams, Doug Wiens, and Geoff Abers.
First land data now available! All data (land and OBS) are at the IRIS DMC, network code XO (2018-2019)
AACSE is deployed! The land array was deployed May-June 2018, and the OBSs finished deployment on July 20 2018
The AACSE deployment has been funded and is scheduled for spring, 2018 deployment!
The AACSE plan will be presented and discussed at the September 2017 OBS Workshop in Portland, Maine!
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.
Download the slides of the webinar (PDF, 8Mb)
Presenters: Susan Schwartz, Geoff Abers, Emily Roland, Rob Evans, Doug Wiens, Jeff Freymueller
- Alaska Amphibious seismic data available
- The Alaska Amphibious Community Seismic Experiment is back! Follow the blog.
- EOS ARTICLE: Examining Alaska’s earthquakes on land and sea, Abers, G. A., et al. (2019) Eos, 100, https://doi.org/10.1029/2019EO117621. Published on 26 March 2019.
Apply to Sail with the Alaska Amphibious Community Seismic Experiment.
Application Deadline is now passed
Cruise Dates (+/- 5 days; arrive 2 days before departure date):
- Leg 1: June 6 – June 24, 2019 (R/V Marcus G. Langseth: active source seismic survey)
- Leg 2: Aug 10 – Aug 29, 2019 (R/V Sikuliaq: passive OBS recovery)
- Leg 3: Aug 27 – Sep 12, 2019 (R/V Marcus G. Langseth: passive OBS recovery)
Graduate students and scientists at all career stages are invited to sail with the Alaska Amphibious Community Seismic Experiment (AACSE) aboard one active source seismic cruise during late Spring 2019, and two OBS recovery legs during the late summer and early fall of 2019. The AACSE is major shoreline-crossing community experiment focusing 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. Data are collected during the 15-month experiment using 75 broadband ocean bottom seismometers (OBS) and 30 land stations.
- OBSs will be recovered by two legs in August aboard the Global-Class R/V Sikuliaq and in September aboard the R/V Langseth. Participants will be involved with all aspects of the scientific process by assisting in OBS recoveries and with multibeam bathymetry data, documentation of the expedition, preparation of cruise reports, and documenting the cruise via social media.
- An active source seismic cruise will be conducted aboard the R/V Langseth in June. This cruise will include an educational component for those interested in learning about marine active source imaging methods. Duties of participants on this cruise will include keeping acquisition logs, acquiring multibeam bathymetry and 3.5 KHz data, documentation of the expedition, preparation of cruise reports, and documenting the cruise via social media.
The PI team anticipates that berths for 4 to 6 additional students or scientists will be available on each leg. The cruises will be aboard working vessels with 24-hours operations, and participants will be unable to return to shore during the expedition. Participants should anticipate difficult conditions including rough seas, long hours, close quarters, constant noise, foul odors, and limited medical facilities. Travel costs to and from the departure and arrival ports, meals, and lodging will be paid for Apply to Sail participants, but no stipend is included.
To apply to sail with the AACSE cruise, each applicant should submit a 2-page CV, a brief statement of interest, and a statement of relevant experience. Applicants who will be graduate students during the summer/fall of 2019 should also submit a letter of support from their graduate advisor. Applications are now closed. Please direct any questions about the Apply to Sail application process to Aubreya Adams (aadams (at) colgate.edu). Questions specific to the passive source cruises should be directed to Aubreya Adams, and questions regarding the active source cruise should be directed to Anne Becel (annebcl (at) ldeo.columbia.edu).
Applications are now closed
The Alaska Amphibious Community Seismic Experiment (AACSE) Team is pleased to invite applications from undergraduate students to join a short course on the Tectonics and Seismicity of the Alaskan Subduction Zone. The short course will be based in Kodiak, Alaska June 14-23 (±2 days) and will include a three-day workshop followed by field work with seismic instrumentation.
During the workshop, participants will learn earthquake science and tectonics, will be introduced to seismic theory and data, and will explore the earthquake geology of the Kodiak region. Following the workshop, students will join in the recovery of a 400 station nodal array across Kodiak with members of the science team.
Applicants should anticipate that this short course will require a 24/7 commitment during the course, will involve work early in the morning and late at night, and require shared accommodation. This no-credit short-course is tuition free, and transportation, room and board will be provided for approximately six students selected to attend the short course, but no stipend is included.
Applications from current sophomores, juniors, and seniors pursuing a degree in geoscience, physics, computer science, applied mathematics, engineering or related majors at a US institution are encouraged.
Applicants should submit the following information by April 1:
- No more than 2-page resume
- No more than 1-page Statement of Interest
- List of relevant classes
- Name and email address for one professional reference. Applicants should ask the reference writer to submit a letter of reference via email to aadams (at) colgate.edu by April 1.
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