Written by David Phillips, Andria Ellis, and Shelley Olds
30 November 2018
A Mw 7.0 earthquake occurred at 17:29:28 UTC on November 30, 2018 (08:29:28 local), 13km N of Anchorage, Alaska. For more information, see the USGS Earthquake Hazards Program event and the Alaska Earthquake Center pages.
GPS/GNSS Real-time Data Streams
Signals from this event were recorded by 22 GPS/GNSS stations within 1000 km of the epicenter operated by UNAVCO that were streaming high rate (1-sps / 1 Hz) data in real time (Figures 2 and 3). These data allowed peak ground displacements (PGD) to be calculated automatically from the displacement traces within seconds of the earthquake (Figure 3). Dynamic ground displacements of several centimeters were recorded by the real-time sites as the surface wave generated by the earthquake propagated away from the epicenter. The displacements were large enough and recorded by enough sites to determine the event to be ~M7 within 120s of the earthquake occurring. Note: figures and findings are preliminary and subject to revision.
GPS/GNSS Data - Custom Downloads for Post Processing
UNAVCO is downloading high-rate 1-sps (1 Hz) data from ~165 GPS/GNSS stations operated by UNAVCO within ~1500 km of the epicenter for a 3-day time window around the event (± 1.5 days). In addition, 5-sps (5 Hz) data will be downloaded from a subset of these stations for a 6-hour time window around the event (± 3 hours). A map of downloaded stations is shown in Figure 2. When downloaded, these data are available from the UNAVCO high rate data ftp site.
Coseismic offsets from this event will be estimated by the GAGE GPS Analysis Center Coordinator (ACC), Professor Tom Herring (MIT). Preliminary offsets will be tabulated and published in an event (*.EVT) file available from the UNAVCO data products ftp site. As more data and final orbits become available, the ACC will also produce a “final” offset solution, as well as offsets estimated from Kalman filter time series analyses. Final and Kalman filter offset files will be added to the event file at the event products ftp site.
Borehole Strainmeter Data
UNAVCO has produced a fully processed 1-sps borehole strainmeter (BSM) dataset spanning the time period of this event. This dataset can be downloaded from the UNAVCO borehole strainmeter event response page.
USGS ShakeMap for the November 30, 2018 M7.0 Earthquake, 13km N of Anchorage, Alaska. (Figure from USGS)...Read more »
Map of real-time GNSS streaming stations within 1000 km of the epicenter operated by UNAVCO used for Peak Ground Displacement (PGD) analysis and magnitude estimation. (Figure by Kathleen Hodgkinson, UNAVCO)...Read more »
Preliminary real-time GNSS results. Traces show the 1-sps (1 Hz) horizontal ground displacements generated by UNAVCO in real-time. The vertical dashed line shows the event origin time. Blue dots show the...Read more »
Upper plot shows the magnitude of the earthquake estimated using real-time GNSS data. The solid green line shows the GNSS estimate with the dashed green line shows the 95% confidence interval.The dashed blue...Read more »
UNAVCO is downloading high-rate 1-sps (1 Hz) data from ~165 GPS/GNSS stations within ~1500 km of the epicenter for a 3-day time window around the event (± 1.5 days). In addition, 5-sps (5 Hz) data will...Read more »
Map of GNSS stations nearest the epicenter from which UNAVCO is downloading high-ratedata for this event. UNAVCO is downloading high-rate 1-sps (1 Hz) data from ~165 GPS/GNSS stations...Read more »
Coseismic GNSS displacements estimated by the Nevada Geodetic Laboratory, University of Nevada, Reno, from the 2018-11-30 M7.0 Anchorage earthquake. The event was over 40 km deep with a normal slip style...Read more »
Peak ground displacement scaling using high-rate GPS waveforms recorded during the November 30, 2018 M7 Anchorage earthquake. Seven nearby stations were processed using IGS Rapid orbits and the TRACK software...Read more »
A GNSS point source centroid moment tensor solution for the November 30, 2018 Anchorage earthquake using rapidly computed coseismic offsets from the Nevada Geodetic Laboratory (NGL). Green's functions are...Read more »
Waveforms for site AC32, showing peak displacements of greater than 10 cm. (Figure from Pacific NW Seismic Network)....Read more »
Waveforms for site AC53, showing peak displacements of greater than 10 cm. (Figure from Pacific NW Seismic Network)....Read more »
UNAVCO Data and Support
- Please contact archive-gpsunavco.org for information on data availability.
- To request access to these and other RT-GPS stations operated by UNAVCO please send an email request to rtgpsunavco.org.
- For information on past event responses, see the UNAVCO Geophysical Event Response page.