Starting this morning, a team of 75 geophysicists will be fanning out around Mt. St. Helens, setting up seismic measuring instruments as part of a massive study that’s intended to accurately map the “plumbing” of our local volcano. Peter Frenzen with the U. S. Forest Service says that an “Equipment Center” is being set up at Woodland Intermediate School, where field crews will collect equipment that’s being set up all around the mountain. 23 seismic charges have been placed in specific locations all around the volcano, and those charges will be set off overnight tonight and tomorrow. The explosions are intended to produce vibrations that will mimic a magnitude 2 earthquake, but those vibrations should probably not be felt. Scientists say that they’ll be recording the vibrations, with a goal of developing a clear picture of the inner workings of Mt. St. Helens. Since the explosive shots are in underground boreholes and will be done at night, there will be little to see when the charges are detonated. However, you can track the shots and see some of what the scientists are seeing by going to the Pacific Northwest Seismic Network website.