September 15, 2017 LT: I can describe how a volcano works. No BBC today TODAY: 1. Notes over volcanoes.—Copy all red in notebook “NOTES” 2. Watch Mt. St. Helens video and copy this question and answer this in your “NOTES” section of notebook: What would I do if I lived near a place where a volcano could erupt? (ex: evacuate, stay, watch, use an underground bunker) and explain why you would do that.

VOLCANIC ERUPTIONS Volcanic eruptions- usually occur near plate boundaries... on land or sea (notice next slide) LAVA (molten rock) - pushes up through the Earth's crust at a weak point ... the lava solidifies and builds up to form mts. / volcanoes. A. Mount Rainier, Washington 14,410 B. Mount Hood, Oregon 11,249 C. Mount St. Helens, Washington 8,365 D. Lassen Peak 10,457 E. Mount Fuji, Japan 12,388 F. Harney Peak 7,244

Cascade Range-WA/OR/CA

The Columbia River crosses the Cascade Range and flows into the Pacific Ocean.

Mount Rainier, the highest mountain in the Cascade Range- 14,410 feet Mount Rainier, the highest mountain in the Cascade Range- 14,410 feet. Seen in the background (left to right) are Mount Adams, the peak of Mount Hood, and Mount St. Helens.

Mt. Rainier (WA) 14,410

Mt. Hood—11,249’ Oregon’s highest peak

Mt. Hood reflected in Mirror Lake

Mt. St. Helens—9,600’ (Before the eruption)

After the eruption—8,365’

Lassen Peak—only other volcano in N.A. to erupt (1917)

Lassen Peak, CA 10,457’

Mt. Fuji—12,388’

Harney Peak—7,244

VOLCANIC ERUPTIONS " RING OF FIRE " ( pg. 49 ) area outlines the Pacific Ocean volatile area with a high degree of earthquakes and volcanic eruptions... activity the result of Pacific plate in a constant state of motion (grinding / colliding)

Side vent—this blew out at Mt. St. Helens Typical volcanic Eruption--vertical

Mt. St. Helens— Lateral Eruption Atypical—was not expected nor predicted.

A Forest Flattened

The Deadly LaHar

Ash layers after the eruption