Category Archives: FAQ

These are recent or frequent questions about volcanoes, volcanology, or who knows what!

Why are there so many volcanoes in the Pacific Northwest and Alaska?

  The distribution of volcanoes in the northwest and Alaska is the result of plate tectonics. In the northwest, the oceanic Farallon Plate is being pushed beneath (subducted) the continental margin of the North American Plate. When the subducted plate … Continue reading

Posted in FAQ

How do volcanoes affect the atmosphere and climate?

This photo shows the large white billowing eruption plume from Rabaul being carried in a westerly direction by the weak prevailing winds. At the base of the eruption column is a layer of yellow-brown ash being distributed by lower level … Continue reading

Posted in FAQ

How does a thermocouple measure the temperature of lava without melting?

A thermocouple works on the principle that the electrical resistance at the point where two wires of different composition join, is very sensitive to the temperature. So…a thermocouple consists of two wires joined to an electrical source. Current passes through … Continue reading

Posted in FAQ

How do volcanoes help scientists learn about the Earth’s interior?

The deepest samples of the Earth’s interior brought up from drill holes come from a depth of 12 km . . . . volcanoes provide direct samples of the Earth’s interior from much greater depths . . at least 100 … Continue reading

Posted in FAQ

How do Volcanologists predict volcanic eruptions?

The prediction of volcanic eruptions is difficult because, to be of practical use, they must be made before eruptions! Its a lot easier to see patterns in monitoring data after an eruption has occurred. But great progress has been made … Continue reading

Posted in FAQ

What tools do Volcanologists use to study volcanoes?

Volcanologists use many different kinds of tools including instruments that detect and record earthquakes (seismometers and seimographs), instruments that measure ground deformation (EDM, Leveling, GPS, tilt), instruments that detect and measure volcanic gases (COSPEC), instruments that determine how much lava … Continue reading

Posted in FAQ

How does magma form and what makes it erupt?

Magma forms from the partial melting of mantle rocks.  These little blobs of melt migrate upward and coalesce into larger volumes that continue to move upward. As they rise, gas molecules in the magma come out of solution and form … Continue reading

Posted in FAQ