Passage A — Many people living in North America often think of volcanic eruptions as something that happens far away. We are more likely to see stories in the news of hurricanes, tornadoes, or forest fires affecting the United States. However, eruptions can and do happen in North America. One recent example is the eruption of Mt. St. Helens on May 18, 1980. The volcano caused the deaths of 56 people, destroyed the picturesque scenery the mountain was known for, and reshaped the landscape for years to come. While the 1980 eruption of Mt. St. Helens is known as a recent natural disaster, there is geographic evidence suggesting the volcano has erupted many times throughout history. In fact, before European settlers arrived, the mountain was known as Louwala-Clough, or Smoking Mountain, by the Native American tribes living in the area. This suggests the mountain has a long history as an active, though sleeping, volcano. Additionally, several smaller eruptions were documented in the 1800s. However, the lack of major eruptions allowed the mountain to develop as a tourist destination.

Passage B — On May 18, 1980, Mt. St. Helens sent a huge plume of ash, gas, and rock soaring into the sky. This devastating eruption led to the death of 56 people in addition to permanently changing the surrounding landscape. It remains one of the most disastrous volcanic eruptions in recent history because of the destruction it caused.

Mt. St. Helens is located in the Cascade Mountain Range in Washington, U. S. It is part of the Ring of Fire, a geologically significant area of the Pacific known for being home to over 160 active volcanoes. Volcanoes are active if they have erupted at least once in the last 10,000 years. Mt. St. Helens is a stratovolcano, which means it is a steep-sided, mostly symmetrical cone built up of many layers of volcanic rock and ash. These volcanoes often have violent, explosive eruptions.

Based on the information in Passage A and B, why is Mt. St. Helens known as an active volcano?

a
The Cascade Mountain Range in Washington is part of the Ring of Fire that contains over 160 active volcanoes.

b
Throughout history, Mt. St. Helens has been known to erupt regularly, causing the death of 56 people every year.

c
Volcanoes are active if they have erupted in the last 10,000 years, and Mt. St Helens erupted only a few decades ago, in 1980.

d
When Mt. St. Helens erupted in 1980, 56 people were killed and the surrounding landscape was changed forever.