Actually, the drain tunnel is approx 4.7 miles north. The tunnel is not under the volcano. It’s under a mountain ridge near “Harry’s Ridge” - named after 84yr old “Harry Truman” who died in the May 1980 eruption. (btw- Harry was a big cat lover. He refused to leave even though the eruptions & earthquakes were getting larger in the days prior. He did admit he was getting nervous).
The “uplift in the tunnel” is interesting as it is away from the base of the volcano. There have been microquakes in the ridges North of Mt St Helens while the current elevated level of on/off swarming is going on.
http://www.cotf.edu/ete/modules/volcanoes/vtruman.html
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Harry Truman and His 16 Cats
Harry Truman was the friendly, 84-year-old owner of the rustic Mount St. Helens Lodge on the old south shore of Spirit Lake. The lodge was his home, and his 16 cats were like family. He had spent a lifetime on the slopes of Mount St. Helens and considered the mountain a friend. Thus, when the volcano awoke early in 1980, Harry and his cats would not leave. As spring progressed, volcanic activity grew terrifyingly violent and the Governor of the State of Washington established restricted entry zones around the mountain with the intent of evacuating everyone except a few scientists and security personnel. Even then, Harry and his cats would not leave. On Saturday afternoon, May 17, 1980, state officials tried for what turned out to be the last time to get Harry to leave. He would not go. Early the next morning, Mount St. Helens exploded. The whole north side of the mountain collapsed in a giant avalanche of rock and debris that roared across the lodge at speeds near 100 mph, obliterating the lodge and burying the site to a depth of about 50 meters. No trace was ever found of Harry or his cats.
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Hopefully we’ll see Harry, if not his cats, in heaven.