On May 18, 1980, the Mount St. Helens volcano in Washington State erupted after a large earthquake, leaving 57 people dead and destroying 250 homes. The event was recorded as the deadliest and most economically devastating volcanic event in the history of the United States. As The New York Times described, “Mount St. Helens exploded at 8:39 a.m. today with a thud felt 100 miles away and with a drifting column of steam and pumice that turned day into night.”
Two months before the eruption, there had been a magnitude 4.2 earthquake at Mount St. Helens. A bulge grew on the mountain’s north side by the end of April, which indicated to experts that magma might be rising and that there was the possibility of a large explosion. The authorities asked residents to evacuate, but a few chose not to, including an 83-year-old Harry Truman (no relation to the former president), who became a minor celebrity when he refused to evacuate his home. Mr. Truman’s body was never found after the 5.1 magnitude quake resulted in a huge collapse on the mountain.
The United States Geological Survey estimated that the eruption of gas and rock traveled 80,000 feet into the air and traveled 300 miles per hour as it covered the area within 230 square miles of the volcano. It destroyed the surrounding forest and immediately killed everything in its path. The 600-degree Fahrenheit gas and rock caused the mountain’s snow to melt, creating mud flows known as “lahars.” The eruption caused an estimated $3 billion in damage.
Connect to Today:
After the eruption, Mount St. Helens was designated as a national volcanic monument for “research, recreation and education.”
A 2009 Times article examined the battle over the future of the site. Those in favor of granting greater public access to the mountain believed it should become a national park, which would bring better financing to the area. Mount St. Helens remains primarily a research zone.
Consider the more general question posed in the article: “How do landscapes recover after violent disturbance?”Given the increase in such events in the United States in recent years, what are your thoughts on how habitats and communities can best heal and move forward after a natural disaster has occurred?
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Eruption of Mount St. Helens 1980
On May 18, 1980, Mount St. Helens erupted and killed fifty-seven people. This was the most recent earthquake in the main forty-eight states since 1915. Mount St. Helens is a stratovolcano located in the state of Washington. A stratovolcano is made up of hardened pumice and lava. Before 1980, the last eruption of Mount St. Helens was between 1840 and 1850. The volcano did not happen overnight however, it was caused by multiple earthquakes and lots of pressure buildup through time. The Mount St. Helens volcano eruption was the most recent volcanic eruption that did significant damage in the United States.
The formation of Mount St. Helens millions of years ago is the reason why the eruption was so violent. The Juan de Fuca Ridge, which lies between the Pacific and Juan de Fuca plate pushes the two plates in opposite directions causing the Juan de Fuca plate to sub duct underneath the continental plate causing a subduction zone and large pieces of rock are pushed into the opposite plate causing a mountain to form. The magma that the Mount St. Helens produces rises from the mantle to inside the volcano when water is released and the material becomes less dense and it’s melting temperature is lowered, causing it to rise up. The magma sits in the magma chamber and volatiles and minerals are slowly released from the magma because of pressure. Eventually, the magma creates too big of a blockage of the volcanic cone and causes a sudden, explosive eruption, much like that of 1980.
From 1840 to 1850 until 1980, Mount St. Helens remained dormant and had no signs of activity, which is common for stratovolcanoes. Many stratovolcanoes have long dormant periods followed by active periods. On March 15, 1980 three small earthquakes were recorded on seismographs that happened underneath the mountain. Scientists believe that the earthquakes were caused by magma running below the volcano. The magma caused an earthquake underneath because the...