By: Alvin Wilson Staff Writer
It has been more than 35 years since Mt. St. Helens, the most active volcano in the Pacific Northwest, erupted in 1980, and scientists are still discovering more about it.
According to a report released Wed. Nov. 4, 2015, a series of large magma chambers have been mapped miles underneath the volcano. Researchers believe the way these magma chambers are aligned could explain the 1980 eruption.
Researchers have mapped two significant chambers: a large chamber 5 to 12 kilometers below the mountain, and an even larger one 12 to 40 kilometers below the mountain.
Scientists are able to map deep magma chambers by using sensitive instruments called seismometers.
Seismometers are extremely sensitive to vibrations, and can pick up movement miles beneath the Earth’s surface.
Since vibrations travel more quickly through hard rock than through magma, scientists are able to map out the size of the chambers by taking note of where the vibrations slow down and speed up.
In order to get an accurate picture, researchers had to use 2,500 seismometers to record the vibrations from 23 large explosions.
According to the images the researchers have compiled, Mt. St. Helens isn’t the only volcano supplied by these large magma chambers. Mt. Adams and a group of dormant volcanoes called the Indian Heaven volcanic field are also likely supplied by these chambers.
The researchers will leave 75 seismometers in pace near Mt. St. Helens in order to collect more data.
Even though it hasn’t fully erupted since 1980, Mt. St. Helens is still considered a high-risk volcano, but researchers believe these new findings will help them find earlier signs of a possible eruption.
