Next-Generation Volcano Monitoring at Mount Rainier, Washington

Date: 4/26/2019

Time: 02:30 PM

Room: Puget Sound

Over the last 2,600 years Mount Rainier has produced at least 8 large lahars (most recently ~1500 C.E.) that inundated now heavily populated areas of the Puget Sound Lowland. Many of these lahars occurred during eruptive episodes, but scientists have found no geologic evidence of an eruption at the time of the most recent large lahar. Hydrologic modeling indicates that these flows could reach small communities near Rainier within 20 minutes and larger Puget Sound communities within an hour. Slope-stability analyses suggest that the western flank of Rainier is particularly vulnerable to a future gravity-driven collapse, which could generate a large lahar with little or no warning.

Volcano monitoring systems are a key strategy for lahar-hazard mitigation at Rainier. For the last two decades there have been two separate systems in operation: a real-time seismic-and-GPS-monitoring network, jointly operated by the Pacific Northwest Seismic Network and USGS Cascades Volcano Observatory (CVO); and a lahar-detection system (LDS) with geophones and tripwires installed along two drainages originating at Rainier, designed and installed by CVO in 1998 and operated by Pierce County (Washington) Emergency Management (PCEM) from 1998 to the present. The two systems operate autonomously, with LDS stations transmitting average seismic amplitudes every two minutes.

In 2016 CVO began working with PCEM officials to upgrade volcano monitoring capabilities at Mount Rainier. The first steps have included upgrading LDS sites with modern instruments (broadband seismometers, infrasound, webcams) and real-time telemetry, and integrating these sites with the real-time volcano-monitoring network. Future work includes new sites on the west flank of the volcano and along its other river drainages, and implementing algorithms for detecting and tracking moving flows. When finished, the integrated network will include more than 30 monitoring stations, making it one of the densest volcano-monitoring networks in the world.

Presenting Author: Seth C. Moran

Authors