TY - JOUR T1 - Enhanced Regional Earthquake Catalog with Alaska Amphibious Community Seismic Experiment Data JF - Seismological Research Letters Y1 - 2022 A1 - Ruppert, Natalia A. A1 - Barcheck, Grace A1 - Abers, Geoffrey A. AB - The Alaska Amphibious Community Seismic Experiment (AACSE) comprised 75 ocean‐bottom seismometers and 30 land stations and covered about 650 km along the segment of the subduction zone that includes Kodiak Island, the Alaska Peninsula and the Shumagin Islands between May 2018 and September 2019. This unprecedented onshore‐offshore dataset provided an opportunity to compile a greatly enhanced earthquake catalog for the region by both increasing the number of detected earthquakes and improving the accuracy of their source parameters. We use all available regional and AACSE campaign seismic data to compile an earthquake catalog for the region between Kodiak and the Shumagin Islands including the Alaska Peninsula (51° N–59° N, 148° W–163° W). We apply the same processing and reporting standards to additional picks and events as the Alaska Earthquake Center currently uses for compilation of the authoritative regional earthquake catalog. Over 7200 events (both newly detected and previously reported) have been processed with AACSE data. We added about 30% more events, 60% more phase picks, lowered the magnitude of completeness by about 0.2 on average across the region, and improved location errors. All data have been published in public data archives. In addition, we test the machine‐learning earthquake detection and picking algorithm EarthquakeTransformer (EQT) on the AACSE seismic dataset, comparing EQT‐determined P and S picks with the new catalog. EQT is entirely trained on land data, whereas AACSE is amphibious. Overall, EQT finds 59% of P and 63% of S arrivals in the catalog within 300 km epicentral distance. The percent of catalog picks detected by EQT varies inversely with earthquake epicentral distance, and EQT performs particularly poorly on data from earthquakes recorded by instruments in the outer rise. VL - 94 UR - https://doi.org/10.1785/0220220226 ER - TY - JOUR T1 - The Alaska Amphibious Community Seismic Experiment JF - Seismological Research Letters Y1 - 2020 A1 - Barcheck, Grace A1 - Abers, Geoffrey A. A1 - Adams, Aubreya N. A1 - Bécel, Anne A1 - Collins, John A1 - Gaherty, James B. A1 - Haeussler, Peter J. A1 - Li, Zongshan A1 - Moore, Ginevra A1 - Onyango, Evans A1 - Roland, Emily A1 - Sampson, Daniel E. A1 - Schwartz, Susan Y. A1 - Sheehan, Anne F. A1 - Shillington, Donna J. A1 - Shore, Patrick J. A1 - Webb, Spahr A1 - Wiens, Douglas A. A1 - Worthington, Lindsay L. AB - The Alaska Amphibious Community Seismic Experiment (AACSE) is a shoreline‐crossing passive‐ and active‐source seismic experiment that took place from May 2018 through August 2019 along an ∼700  km long section of the Aleutian subduction zone spanning Kodiak Island and the Alaska Peninsula. The experiment featured 105 broadband seismometers; 30 were deployed onshore, and 75 were deployed offshore in Ocean Bottom Seismometer (OBS) packages. Additional strong‐motion instruments were also deployed at six onshore seismic sites. Offshore OBS stretched from the outer rise across the trench to the shelf. OBSs in shallow water (<262  m depth) were deployed with a trawl‐resistant shield, and deeper OBSs were unshielded. Additionally, a number of OBS‐mounted strong‐motion instruments, differential and absolute pressure gauges, hydrophones, and temperature and salinity sensors were deployed. OBSs were deployed on two cruises of the R/V Sikuliaq in May and July 2018 and retrieved on two cruises aboard the R/V Sikuliaq and R/V Langseth in August–September 2019. A complementary 398‐instrument nodal seismometer array was deployed on Kodiak Island for four weeks in May–June 2019, and an active‐source seismic survey on the R/V Langseth was arranged in June 2019 to shoot into the AACSE broadband network and the nodes. Additional underway data from cruises include seafloor bathymetry and sub‐bottom profiles, with extra data collected near the rupture zone of the 2018 Mw 7.9 offshore‐Kodiak earthquake. The AACSE network was deployed simultaneously with the EarthScope Transportable Array (TA) in Alaska, effectively densifying and extending the TA offshore in the region of the Alaska Peninsula. AACSE is a community experiment, and all data were made available publicly as soon as feasible in appropriate repositories. VL - 91 UR - https://doi.org/10.1785/0220200189 ER -