Why finding volcano tremor activity level is important

Looking at an erupting volcano:
Quick have a look at this seismograph. What time was the volcanic tremor the highest? Is it increasing? The answers are kind of important. There is a geothermal plant right next to the lava flow.

The above record is a 6 hour snapshot of a seismograph called PHOD that was located on the slopes of Kilauea Volcano on May 22, 2018. This seismograph is just North of the Puna Geothermal Venture power plant. It is natural for your eyes to be drawn to the bar showing a large earthquake. Now remember the question. During which 15 minute period was the volcanic tremor the highest? Further, is the level increasing, decreasing, or the same? Is the power plant safe?

Comparing tremors on two seismographs
Now have a look at these two seismographs. They look very similar don't they? However, there is a critical difference between the two. One seismograph is located North of the East Rift Zone on Kilauea Volcano, and one is South of the Rift Zone. The date is May 22, 2018 and residents of the town of Kapoho are worried about exactly where lava is most likely to erupt. If it erupts close to one of the seismographs, the flow is likely to go safely into the ocean with little to no property damage. However, if it erupts almost dead center between the two seismographs, then it will go right through the neighborhood.

Without a standard to compare the two seismographs, there is no quantitative way to answer this basic question.

Monitoring for an impending eruption
Here is yet another seismograph record seen on the same volcano and same date. This is a seismograph located up near the highway and it is being watched very carefully. If lava erupts and covers the highway, resident access will be very difficult. Further, the eruption may inundate neighborhoods located down slope.

The dark lines are later in the six hour period for this record. This particular seismograph is problematic. Notice not all the lines are straight. There are baseline shifts. Are those something significant? Which 15 minute period had the most tremors? How do we rate the scale of tremors?

So many questions and so few answers. 

This blog hopes to answer as many questions as possible and provide valuable learning tools that any teacher and class can follow.

This blog was created by Philip Maise

Captain of Hot Buoys Sailing Vessel

Former resident and of Pahoa Hawaii

Attribution: All materials were created by Philip Maise

They may be copied and used for free provided the attribution reads

Materials created by:

Philip Maise, May 2018

Captain of Hot Buoys Sailing Vessel