Data Event Response to the October 19, 2020 M 7.6 Sand Point, Alaska Earthquake

Written by Shelley Olds, Kelsey Russo-Nixon, & Kathleen Hodgkinson
Originally posted 21 October 2020
Last updated 28 October 2020

Event Summary

A magnitude 7.6 earthquake occurred at 20:54:39 UTC (12:54:39 AKDT) on October 19, 2020, 91 km SE of Sand Point, Alaska. For more information, see the USGS Earthquake Hazards Program event page or the Alaska Earthquake Center event page.

The event occured within the Network of the Americas (NOTA) footprint. NOTA is a core component of the NSF Geodetic Facility for the Advancement of Geoscience (GAGE), operated by UNAVCO.

GAGE Response

NOTA GPS/GNSS Real Time Data Solutions
At the time of the earthquake, 25 real-time stations were operating within 1300 km of the epicenter, the approximate radius where dynamic displacements were expected to be greater than 2 cm given the magnitude and death of the earthquake. UNAVCO operates a network of real-time station in the region as part of NOTA. Real-time stations continuously stream high rate (1-sps / 1 Hz) data to the GAGE data center. Typical latencies for real-time stations, the time difference between and observation being recorded on the receiver and it arriving in Boulder, Colorado are less than 1 second.

NOTA GPS/GNSS High-Rate Data for Post Processing
UNAVCO is downloading 1- and 5-sps (1 and 5 Hz) data from all NOTA GPS/GNSS stations within 1300 km of the epicenter where it is available. These data will be available in RINEX format from the UNAVCO high-rate data ftp site.

GAGE GPS/GNSS Displacement Estimates
The GAGE AC (MIT) inspects the NOTA GPS/GNSS daily positions for significant offsets when they have two to three days of post-event data. Any detected offsets will be posted to UNAVCO’s event directory when they become available.

NOTA Borehole Strainmeter Data
UNAVCO will produce a fully processed 1-sps borehole strainmeter (BSM) dataset for this event. This dataset can be downloaded from the UNAVCO Geophysical Event Data page when it becomes available.

Note: Figures and findings are preliminary and subject to revision.