by Del Tackett
I took this picture from Johnson Ridge. It is named after the geologist who was killed in the Mt. St. Helen’s eruption. He was alternating every other day with another geologist taking turns being flown in by helicopter to monitor the mountain. On May 18, 1980, it was his turn and it was to be his last. When the mountain erupted, he radioed his final words: “…this is it.”
In the foreground, you will see a lot of geological formations. What you don’t see is the original lush forest that was obliterated in the initial blast. That forest would have been about 600 feet below the current surface. The debris from the avalanche, the ash, the mudflows, the pyroclastic flows…all filled it in. An eruption two years later sent a mudflow that carved the huge “Steps Canyon” that is visible just left of the center of the picture at the base of the mountain cone. All the other canyons around and below it were also carved out in a matter of hours as well.
What happened at Mt. St. Helens is changing the way an increasingly number of geologists look at the world around us. For nearly 200 years, the notion of a very old earth was precipitated primarily by how geologists began to think that “the present is the key to the past”. This meant that one was supposed to interpret geological formations by extrapolating backwards into time using the processes that we see in operation today. The problem is that most all of the geological formations that we see today were not caused by present processes but were caused by catastrophic events. The old “uniformitarianism” thinking is what led many to believe that the Grand Canyon, for example, was carved out by the Colorado River over millions of years. Most people probably still believe that to be true because that was what they were taught. In reality, the evidence there and the evidence seen at Mt. St. Helens has caused most geologists to now embrace a catastrophic event for the carving of the Grand Canyon. This is an encouraging change because the key to the geological past is not the present, but the key to the geological past is found in catastrophic events.
Although Mt. St. Helens is quite minor in comparison to other catastrophic events, including other North American eruptions, it was one that was fully observed and has been studied extensively. Those studies are now beginning to cause many to question the old geological story that you and I were taught in school.