On what date did the 1980 eruption of Mount St. Helens, in which "Crater Glacier" was formed, occur?
Crater Glacier The Crater Glacier (also known as Tulutson Glacier) is a geologically young glacier that is located on Mount St. Helens, in the U.S. state of Washington. The glacier formed after the 1980 Eruption and due to its location, the body of ice grew rapidly, unknown to the public for nearly 20 years. The glacier once contained ice caves in the smooth ice before the 2004-2008 volcanic activity. The growth of the lava dome and volcanic eruptions from 2004 to 2008 significantly altered the appearance of the glacier. In the same time period, several agencies decided to put an official name on the glacier which, at first, was Tulutson Glacier. A later decision made Crater Glacier the official glacier name. Despite the volcanic activity, the glacier continued to advance and by mid-2008, the glacier completely encircled the lava domes. In addition, new glaciers (rock or ice) have formed around Crater Glacier as well.
Hawaiian eruption A Hawaiian eruption is a type of volcanic eruption where lava flows from the vent in a relatively gentle, low level eruption; it is so named because it is characteristic of Hawaiian volcanoes. Typically they are effusive eruptions, with basaltic magmas of low viscosity, low content of gases, and high temperature at the vent. Very little amounts of volcanic ash are produced. This type of eruption occurs most often at hotspot volcanoes such as Kīlauea on Hawaii's big island and in Iceland, though it can occur near subduction zones (e.g. Medicine Lake Volcano in California, United States) and rift zones. Another example of Hawaiian eruptions occurred on the island of Surtsey in Iceland from 1964 to 1967, when molten lava flowed from the crater to the sea.