Orting, Washington

MZEC Consulting Geographic Location and Physical Site

● Orting is a city in Pierce County, Washington State. ● The city has a total area of 7.25 km2. ● Located 60km South of Seattle and 30km southeast of Tacoma. ● Elevation: 60m ● Population census 2014: 7,266 (84% increase since 2000). Subduction

❖ Movement between tectonic plates where one moves (subducts) under the other. ❖ Cascadia Subduction Zone: ➢ A convergent plate boundary from Vancouver Island to California. Orting is situated along the boundary. Tectonic processes in the zone include accretion, subduction, earthquakes, and active volcanism. ❖ Cascade Volcanos: ➢ Dangerous due to eruptive history and potential. ➢ Past landslides from Cascade volcanoes have affected areas hundreds of kilometers from their point of origin.

Volcanic History of Mt. Ranier

Volcano Type: Stratovolcano

Started to grow 500,000 years ● ago on eroded remains of an earlier ancestral Mt. Ranier that was active 1-2 million years ago

Last Eruption: early 19th century, but last truly large eruption over 1000 years ago Hazards of Mt. Ranier

● Lava Flows - primary hazard to people is low, but contact with snow and ice will generate floods and lahars ● Ash/Tephra Fall - explosive magma and rocks ● Pyroclastic Flows - mix of hot lava blocks, pumice, ash and volcanic gas; destroys everything in its path ● Lahars - hot and cold mixture of rack fragments; acts like wet concrete Risks to the Town of Orting ● Puyallup River and Carbon River flow off of the Mountain and surround Orting converging North of the city ● The town is built on a previous Lahar that is 9 meters deep ● Without prior warning, citizens would have 45 minutes to evacuate with only one main highway heading north out of the city Recommendations

● At this point there is an insufficient evacuation plan for the Orting School District which poses further risk if a College is built in this area.

● Before any project can move forward we recommend that the Bridge for Kids project be completed.

● “No less likely to erupt than 30 years ago...danger is that people are moving much much closer”