Monitoring Lassen

The Lassen Volcanic Center sits atop a hydrothermal system that might one day be the scene of hydrothermal explosions. Researchers keep watch over this area, and a new form of monitoring may soon be added to their arsenal.

graph with error bars

Change in velocity of seismic waves at LVC over time, showing its response to the Greenville quake (top) as well as to snow (bottom).

The Berkeley Seismology Lab’s Taka’aki Taira, along with Florent Brenguier (Université Grenoble Alpes) have developed a system that analyzes seismic “noise” -- vibrations without a distinct source. This recorded ambient noise, from six stations in the Northern California Seismic Network around Lassen Peak, is automatically processed to pinpoint changes in how fast seismic waves go through this area, which can indicate changes in tectonic stress in volcanic areas.

In a new paper, highlighted in last week’s SpringerOpen blog, Taira and Brenguier track the seismic velocity for the Lassen Volcanic Center over more than four years. The differences in seismic velocity over time show the effects of the M 5.7 Greenville earthquake as well as the stresses associated with snow (changes in groundwater and surface loading.)

But the monitoring system could be improved. The current system outputs a daily velocity change. With more computing power, researchers could perform the massive cross-correlation computations required to give an hourly update, enabling researchers to detect changes in velocity that accompany and perhaps precede volcanic activity.

Read more about this topic at the SpringerOpen blog.