The 2019 Ridgecrest Earthquake Sequence Tests Integration of Real-Time GNSS for Earthquake Early Warning

Session: Advances in Real-Time GNSS Data Analysis and Network Operations for Hazards Monitoring [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

We know that magnitudes derived using a few seconds of the P-wave saturate for earthquakes larger than ~M7. This short observation window does not capture long period signals and further it may take several seconds for large earthquakes to evolve. The ground displacements associated with a large earthquake, however, do appear to scale with moment magnitude and therefore, in theory, geodetic measurements could provide the best estimate of magnitude in real-time. The July 6th 2019 M7.1 mainshock of the Ridgecrest, CA sequence provided a unique opportunity to test these ideas using the real-time GNSS signals captured by the NSF funded Network of the Americas (NOTA).

At the time of the M7.1 rupture, over two hundred NOTA GNSS stations were operating in real-time within 250 km of the epicenter. In this presentation, we show the latencies and completeness with which the raw GNSS data arrived at the NOTA Network Operations Center at UNAVCO, Boulder, CO. We also show the real-time position solutions distributed by UNAVCO while rupture was still ongoing and demonstrate that the displacements recorded by near-field NOTA stations indicated that the event was ~M6.9 within 13 seconds of the origin time. The Ridgecrest sequence demonstrates the key role that GNSS can play in earthquake early warning systems and gives us insight on the requirements for operational integration of RT-GNSS into Earthquake Early Warning systems in CA, OR and WA.

Presenting Author: Kathleen Hodgkinson

Authors