The Transportable Array (TA) team plans to remove the remaining Alaska TA stations this summer during the 2021 field season. This follows a postponement due to local, state, and federal travel restrictions in response to the pandemic and with the support of the National Science Foundation (NSF). Data telemetry ceased on May 1, 2021 and the Array Network Facility (ANF) will continue to support archival at the IRIS Data Management Center along with processing onsite baler media as it is returned from removals.
The timeline of operations, transitions, and removals for the Alaska TA stations is being executed as follows:
- In Fall 2019, 43 stations were transferred to the Alaska Earthquake Center under the AK network code, leaving 151 operated by IRIS.
- By May 1 2020, 24 additional stations were transitioned to Alaska Volcano Observatory and the Alaska Earthquake Center.
- During the 2020 field season, all remaining stations continued to be operated with data telemetry and archival at the IRIS Data Management Center. Station removals were limited while adhering to all local, state, and federal travel restrictions due to the pandemic as well as employing a limited contact strategy developed specifically for the Alaska TA project.
- By September 30 2020, 45 stations were transferred to the Alaska Earthquake Center under the AK network code as part of a funded award in response to the 19-048 NSF Dear Colleague Letter.
- On May 1 2021, telemetry was turned off at the remaining stations and real-time data collection ceased.
- Five (5) stations that have been transferred will continue to be archived under the TA network until a later transfer date (F28M, P32M, A36M, C36M, EPYK).
- During the 2021 field season, all remaining non-transferred TA stations will be removed. All baler media returned before September 1 2021 will be processed at ANF.
A subset of Alaska Transportable Array stations have been transitioned to other network operators. Seismic data from these transferred stations is still archived and available via the IRIS Data Managment Center, with a change of network code and, in some cases, a change in sample rate or channel/location code. This might require adjusting data retrieval scripts. The full list of adopted or continuing Transportable Array stations is available under the virtual network _US-TA-ADOPTED.
Station hosts and the public can view data in webicorder or event views from stations or locate the nearest station with real-time data using the IRIS Station Monitor app.
A paper on the Alaska Transportable Array has been published in a focus section of Seismological Research Letters in November 2020 and is available online. A longer format final report is in preparation and will be made available on the USArray Publications web page.
Scientific results from Alaska EarthScope have been featured in a weekly seminar series this spring and culminating in a virtual workshop held May 10-14, 2021.
IRIS would like to thank the National Science Foundation for their continued support of the Alaska Transportable Array project through NSF Award EAR-1261681.