1. Reflection
In the worksheet that you filled out earlier today for the vulnerability analysis, there was a column labeled “Reflections.” Use that column to compare the vulnerability analysis of your geographic location to the actual impacts of Mount Rainier’s eruption at your site.
These are slides for the Mount Rainier eruption scenario in Unit 6, Living on the Edge.

2. Pre-Eruption Mt. Rainier Green River Puyallup River Tacoma
Image from Google Earth. Map data: Google, Landsat.
This is the area west of Mount Rainier prior to the eruption scenario described in this activity. The mountain in the top right corner of the image is Mount Rainier. The port of Tacoma is in the middle of the bottom of the image. Orting and Kent are visible, as are the Puyallup and White River valleys. The image shows some of the kinds of features that are important in the eruption – the high relief near the mountain and the river valleys and floodplains further out.
Tacoma

3. Phase 1 of eruption (June 12) characterized by small lahars and ash column
Public domain image. Source: USGS, Accessed: September 23, 2014
(Image of Mount Pinatubo)
Phase 1: Early in the morning of June 12, a series of tremors and eruptions shakes Mount Rainier. During this time, some small lahars are produced and a column of ash about 10 km tall is erupted from the vent.
USGS

4. Phase 2 of eruption (June 12-14) characterized by pyroclastic flows and tall eruption column
Public domain image. Source: USGS, Accessed: September 23, 2014
(Photo of Mount St. Helens, August, 1980)
Phase 2: Between June 12 and June 14, several pyroclastic flows cascade down the slopes of Mount Rainier. Vertical columns of ash are occasionally seen reaching as high as 20 km for brief intervals.
USGS

5. MAIN ERUPTION
Flank collapse triggers debris avalanche, eruption column, pyroclastic flows, lahars
Public domain image. Source: USGS Accessed: September 23, 2014
(Photo of Chaitén, Chile)
Phase 3: In the afternoon of June 15, a large vertical eruption triggers collapse of the weak west flank of Mount Rainier, causing an avalanche of debris from the mountain. Debris is carried up to 10 km from the summit. This is followed by a tremendous lateral blast and the eruption of a column of ash 30 km high. Much of the ash is transported east by winds, covering Yakima, though western Washington was blanketed by a thin layer of ash as well.
USGS

6. Pyroclastic flow deposits
Collapsed flank
Pyroclastic flow deposits
Public domain image. Source: USGS Accessed: September 23, 2014
(Mount St. Helens)
Several large pyroclastic flows and surges occur between the time of the collapse and the evening of June 15. These travel as far as 25 km from the summit along the Nisqually River valley, where flows are channeled by steep topography. Pyroclastic flows reach the town of Ashford, just outside the entrance to Mount Rainier National Park.
USGS

7. Green Puyallup Nisqually Cowlitz Olympia
Map: P. Selkin. Data modified from USGS Open-File Report , Accessed September 23, 2014.
Map of region affected by the June 15 eruption of Mount Rainier. Not shown: ash deposits. Star is state capital at Olympia.
During the main phase of the eruption (phase 3), lahars fed by melting glaciers flow along most major drainages from Mount Rainier. To the west, the Nisqually, Carbon/Puyallup, and White/Green River basins are most significantly affected. Lahars reach Puget Sound at Commencement Bay (Tacoma) and the Nisqually Estuary. Along the Green/Duwamish Rivers between the Kent Valley and Seattle, flooding and high sediment load associated with the lahars causes extensive damage. To the southeast, lahars flow down the Cowlitz River basin.
Nisqually
Cowlitz

8. Pyroclastic flow deposit
Public domain image. Source: USGS Accessed: September 23, 2014
(Mount Merapi, Indonesia)
House near Ashford buried by a pyroclastic flow. Pyroclastic flows affected areas within about 25 miles of the volcano.
Pyroclastic flow deposit
USGS

9. Ash Pyroclastic flows Lahars
Image from Google Earth. Map data: Google, Landsat, P. Selkin.
Lahars cut off all major roads, including Interstate 5, between Seattle and Tacoma, as well as between Tacoma and the state capital, Olympia. Because the lahar damage was primarily south of the SEA-TAC airport, Seattle’s connection with its airport remained intact.
Rail traffic is also disrupted. Most rail terminals in the areas south of Seattle as well as in Kent are flooded briefly. In Tacoma and Orting, rail service is permanently closed due to lahar damage.
Commercial ship traffic into and out of Seattle is disrupted due to sediment discharge from the Duwamish river. Commercial shipping is completely stopped in Tacoma: all terminals are buried or partially buried by lahar sediment.
Flooding causes damage to low-lying businesses in the area south of downtown Seattle as well as in Kent.
Electrical transmission lines, which come to Seattle from north of the region affected by lahars, were not affected. Electrical distribution in the SoDo and port areas, however, was affected by flooding. Significant damage to dams along the affected river systems (Nisqually, Carbon/Puyallup, Green, Cowlitz) has cut power to the Puget Sound area south of Seattle and north of Olympia.
Lahars

10. Lahar deposit
Public domain image. Source: USGS Accessed: September 23, 2014
(Huila, Colombia)
Puyallup River valley covered by Lahar deposits.
USGS

11. Image from Google Earth
Image from Google Earth. Map data: Google, Landsat, SIO, NOAA, US Navy, NGA, GEBCO, P. Selkin.
Seattle sees few direct effects aside from a layer of ash. Flights at SEA-TAC and all other nearby airports and military installations are grounded until ash was removed.

12. Public domain image. Source: USGS http://volcanoes. usgs
Public domain image. Source: USGS Accessed: September 23, 2014
(Pinatubo)
On roads east of the Cascades, ash from the volcano is a driving hazard.
USGS

13. During the eruption cycle, you had to issue alerts based on incomplete information; you did not yet know the full scale of the eruption, or what its damage would be. In fact, a common part of the scientific process involves drawing conclusions from the information you have, and then revising those conclusions when presented with new information. This process of revising conclusions (or, in this case, alert levels) may lead some people to feel that scientists are not trustworthy, or that the conclusion (alert level) is based on opinion. How might you communicate your alerts to the public in a way that takes both the uncertainty and the seriousness of your alert into account?

14. Where should disaster management personnel start their work after (or during) the eruption of Mount Rainier? Compare the need for human assistance (food, water, housing) with economic reconstruction (roads, bridges, ports).
The following three sets of questions are possible prompts for discussions during the last 10 minutes of class. The instructor should choose one of the question slides.

15. Consider that activity such as lahars and secondary eruptions are probably ongoing for months after the main eruption. What is the role of volcanologists in supporting state agencies before, during, and after an eruption like this one? Given that your instruments were probably destroyed in the eruption, prioritize the specific data that you would want to have to provide monitoring analyses to disaster experts.

16. Consider the vulnerability score of a town vs
Consider the vulnerability score of a town vs. overall risk (which includes population, economic impacts, etc.). How can disaster recovery and hazard mitigation managers use vulnerability and risk analysis to prioritize where they should spend time and resources? Should both vulnerability and risk be considered?