May 18 will be the 36th anniversary of the devastating 1980 eruption of Mount St. Helens in Washington State. That eruption was the only significant volcanic eruption to occur in the lower 48 states since 1915, and it was preceded by two months worth of swarming earthquakes. The 1980 eruption of Mount St. Helens produced an ash column that extended 80,000 feet into the atmosphere. It also caused the melting of the snow and ice and even multiple glaciers in their entirety on the volcano. The resulting water caused several large volcanic mudslides, also known as lahars, which extended almost 50 miles from Mount St. Helens itself. The ash from the eruption ended up scattered over 11 states.
Check out the 1980 Mount St. Helens eruption, which occurred after 120 years of dormancy.
The 1980 Mount St. Helens eruption was directly responsible for at at least 57 deaths.
Now CNNis reporting that Mount St. Helensis in the midst another earthquake swarm. Over the last eight weeks, seismographs have recorded over 130 earthquakes beneath Mount St. Helens. Scientists say that most of the current quakes at Mount St. Helens, which is about 95 miles south of Seattle, have had magnitudes of 0.5 or less. The largest quake recorded so far was a magnitude 1.3. The quakes are occurring at a depth ranging from 1.2 to four miles beneath the surface of the Earth, and are too deep and small to be felt by humans.
While the earthquakes at Mount St. Helens are too small to be felt and too small to cause damage in and of themselves, their frequency has caught the attention of scientists. Their frequency has also been increasing since the swarm began on March 14.
The slow recharging process & swarms under Mount St. Helens #volcano , blog by @eruptionsblog https://t.co/JuoWfCKN5i pic.twitter.com/r7H14V22bY
— Dr Janine Krippner (@janinekrippner) May 6, 2016
The U.S. Geological Survey is telling people not to worry, that they don’t believe that Mount St. Helens is going to blow its top again in the immediate future. However, they agency says that the current Mount St. Helens quake swarm is telling scientists something.
“[At this point] there is absolutely no sign that it will erupt anytime soon, but the data we collect tells us that the volcano is still very much alive.”
Seismologists say that, unlike prior to the 1980 eruption, there are currently no “anomalous gases” being emitted by the volcano, nor are their indications that the magma chamber is becoming inflated.
In a nutshell, while scientists don’t believe an eruption of Mount St. Helens is imminent, they do believe that the volcano is “recharging.” After all, small earthquakes are common under and around volcanoes, and indicative of a slip on a small fault. However, because this earthquake swarm is occurring under Mount St. Helens, the deadliest volcano in America, scientists and laypeople alike are taking notice. Following the 1980 eruption, Mount St. Helens became one of the most closely observed and monitored volcanoes on Earth.
And while the current earthquake swarm at Mount St. Helens might not mean that a big eruption is going to happen in the coming days, weeks or months, it does mean that its magma chamber is refilling, reports The Guardian. As the magma chamber refills with hot, molten rock, that molten rock comes into contact with the colder existing rock of the magma chamber, causing more stress on the chamber itself. This “push and pull” is what causes earthquakes like those currently occurring at Mount St. Helens.
“As was observed at Mount St Helens between 1987 [and] 2004, recharge can continue for many years beneath a volcano without an eruption.”
The last eruption of Mount St. Helens was in 2008, and it followed a “surprise reawakening” of the volcano in 2004 when the volcano erupted after almost two decades of dormancy. The years 2004 to 2008 is considered by scientists to have been “a continuous eruption in the form of gradual extrusion of magma.” During that period, Mount St. Helens rebuilt the magma chamber destroyed in the 1980 eruption.
After January, 2008, activity at the volcano quieted down. Now, it appears that Mount St. Helens is waking up once again, and you can bet that the world will be keeping a close eye on the unpredictable volcano.
[Photo Courtesy Of Uncredited Photographer/AP Photo]