Seismo Blog

iMUSH: Adventures in the Field

September 12, 2016

by Lauren Burch

Written by Mika Thompson:

As of the 1st of September, the iMUSH project (Imaging Magma Under St. Helens), a seismic experiment that used 70 temporary seismometers to collect seismic data around Mt. St. Helens, is finished and all stations have been removed. iMUSH has been a great way for perpetually desk-bound seismology graduate students to get outside, wrangle with nature and get some hands-on experience working with the instruments that collect the data we use in our research. It’s also been a unique opportunity to come up with creative solutions to the unforeseen obstacles we encounter along the way. 

Our job as volunteers during the installation was to survey sites, install seismometers and recording equipment, and the power sources to keep them up and running (solar panels and batteries).  Servicing required less lugging around heavy equipment and a lot more driving from site to site, collecting data cards and repairing damage acquired over the winter months or by the local wildlife. 

I’ve been lucky enough to participate in the entire process from install to removal, periodically berating myself when having to deal with the consequences of my own overzealous burying of cables and liberal use of zip ties. Our experiences over the last couple of years have ranged from rewarding (amazing views of Mt. St. Helens, Mt. Adams, and Mt. Rainier) to frustrating (road washouts, flat tires, and broken side mirrors). But the worst sites make the best stories, so I would like to share a couple of my more comical experiences during the removal process. 

On the first day of the removal, Ian and I made our way to a site located in a clear cut on Weyerhauser land.  The site was close to the road and I had been there before, so I figured removing the site would be pretty easy.  Then we encountered our first obstacle.  Wasps.  Lots of wasps.  And they had decided that the back of a solar panel was the perfect place to build a nest. 

So, Ian bravely decided to try and remove the nests with a shovel, but not before suiting up in appropriate wasp-wrangling attire, which involved lots of duct tape and a plastic garbage bag.

He then proceeded to slowly sneak up to the solar panel and gently placed the shovel beneath the first nest.  He was doing great, but right as the nest fell into the shovel he lost his nerve and dropped it.  Now, instead of a nest of sleepy wasps, we had a swarm of angry wasps right under the solar panel.  So we decided to leave and complete the next site and return later with a can of Raid.  

We returned to the site appropriately armed later in the afternoon and were able to spray the 2 nests. Unfortunately, Raid only works when the wasps are in the nest and there were still a quite a few hanging around.  I should add that we were feeling extra cautious, since Ian had just been stung twice while trying to unlock the gate to the Weyerhauser property (apparently those make great nesting places too). So we decided to tie a rope to the panels and drag it away from the swarm.  This proved successful and we were able to disassemble the solar panels after dragging them about 20 feet from the original spot.  The whole process took about 4 hours.  So much for an easy site removal.  

The third day of the site removal, Carl and I made our way to a site in the Gifford Pinchot National Forest.  When we turned off the main road you could barely see the dirt road we were to take to the site, it was so overgrown with saplings.  So we put the car in 4-wheel drive, folded in the side mirrors, and proceeded slowly down the track.  About halfway to the site we encounter a fallen tree.

There is no way we were driving over that.  We then had to decide whether we would park the car and hike about a mile to the site or cut up the tree.  He and I both agreed that we would rather cut down a tree than hike back and forth several times carrying batteries, solar panels, and other awkward heavy things.  So, Carl and I set to chopping up the tree with hedge clippers, a handsaw, and an ax.  We sawed and hacked at the tree for about an hour (both saw and ax were pretty dull).  We managed to get one end free but the other wouldn’t budge.

We tried jumping up and down on it for a while and then eventually realized we had one big tool that we hadn’t tried yet:

Finally! We were free to continue on our way.  And then 50 feet down the road…

*Sigh* well, at least we didn’t need the ax for that one.

Hope you enjoyed reading about our adventures in the field!  If you would like to learn more about the iMUSH project, click this link the iMUSH webpage http://imush.org/.

The Long Trek to MH09

September 8, 2016

by Shelley Chestler

Sometimes uninstalling a seismic monitoring station doesn't go quite as planned. Here is tale of my team's first attempt to take out a particularly stubborn station for the iMUSH (Imaging Magma Beneath St. Helens) project:
Both the Cascade Mountains and the Olympic Mountains are products of subduction, but not all mountain ranges are created in the same way.

Another debris flow avalanche at Mount Baker

June 15, 2016

by Steve Malone

Seismic signals on May 25 are evidence for the size and timing of yet another on of these avalanches.

All the mountains, oceans, and islands on Earth exist because of plate tectonics. Different plate boundaries produce different geologic features: divergent boundaries spread apart to form mid-ocean ridges and rift valleys, transform boundaries slide past one another to form strike-slip faults like the San Andreas, and convergent boundaries collide to form tall mountains, deep trenches, and volcanoes. This type of plate boundary is responsible for the numerous volcanic arcs around the Pacific Rim (often called the “Ring of Fire”), and formed our iconic Cascade Volcanoes. Here in the Pacific Northwest, the Juan de Fuca plate is subducting beneath the North American plate along a convergent plate boundary called the Cascadia Subduction Zone (CSZ). Subduction zones like this are the only fault systems capable of producing very large megathrust earthquakes, but they only do so occasionally - over the last 100 years, there have been 84 earthquakes of magnitude 8.0 or greater worldwide, and only 4 of them were greater than an M9.

 


The simplest answer to the question “Will there be another large earthquake on the CSZ?” is yes. However, the question of “when” is much more difficult to answer. Seismologists don’t know exactly when the next large earthquake will occur on the CSZ, but we do have a good picture of when they have happened over the past 10,000 years. If we divide 10,000 years by the number of ~M9 earthquakes found in that time period, the average recurrence rate for M9 earthquakes along the CSZ is roughly 550 years. We are 316 years past the last great CSZ earthquake in 1700, and we estimate that there is about a 15 % chance that an M9 will occur on this fault within the next 50 years. However, research on submarine landslide deposits shaken loose by big earthquakes indicate that M8+ earthquakes occasionally strike off the coast of Oregon in between “full rip” M9 events. This research suggests that there is a greater probability of reoccurence of a great earthquake in Southern Oregon than off the Washington coast, but there is not a consensus within the geophysical community as to specifically how much greater the hazard is.

One is a guess, and the other is an educated guess.
Earthquakes happen on faults, but where are the faults in Oregon and Washington? The new "Display Faults" tool on the PNSN Recent Events map can help you explore the locations of faults in the Pacific Northwest.

Exotic Events (not erotic events)

April 1, 2016

by Steve Malone

Seismically recorded non-earthquakes now have their own page at the PNSN.

Negative depth earthquakes?

March 30, 2016

by Steve Malone

Why do some earthquakes in our list have negative depths now?

Explosion "Earthquakes"

March 10, 2016

by Steve Malone

Two recent large explosions generated acoustic waves recorded on seismographs.

West Coast Earthquake Early Warning System on the Horizon

February 9, 2016

by Shelley Chestler

Last week the White House hosted the first ever Earthquake Resilience Summit. One of the main goals of the meeting was to discuss the potential for fully funding a west coast earthquake early warning system.

Back-to-back ETS events, maybe

February 6, 2016

by Steve Malone

Following the recent "standard" northern Washington ETS another has apparently started heading south toward Oregon.

Slow Earthquake Trembles beneath Vancouver Island

January 7, 2016

by Shelley Chestler

Did you know that there is a type of earthquake that happens so slowly that we can’t feel it? One of these slow earthquakes is happening under Vancouver Island and northern Washington right now!

A Perspective on Tremor Activity

January 7, 2016

by Aaron Wech

With tremor activity occurring in the Pacific Northwest, it's important to provide perspective.

Don't Sweat the Little Ones

December 14, 2015

by Shelley Chestler

The recent earthquakes around the Puget Sound are probably not indicative of the “big one.”

A new look for pnsn.org

December 4, 2015

by Jon Connolly

The new pnsn.org website aims to provide a better user experience for all devices, prioritize features, and provide robust availability during a seismic event.
The July 2015 New Yorker article “The Really Big One,” by Kathryn Schulz, shook up the Pacific Northwest (PNW) more than any earthquake has since the Magnitude-6.8 Nisqually earthquake in 2001. In the article’s most dooming statement, the head of the Cascadia FEMA division was quoted saying, “everything west of I-5 will be toast.” This assertion scared the living daylights out of PNW residents, creating a sense of terror and hopelessness that was the antithesis of what the article meant to do: to spur the region into preparing for this potentially devastating event.

Unusual earthquake swarm south of Bend, OR

October 23, 2015

by Steve Malone

A somewhat unusual earthquake swarm started early on Oct 22, 2015 in an area about 65 km (40 miles) southwest of Bend, OR (25 km WSW of La Pine, OR). 36 events have been detected and located by the PNSN as of noon on Oct. 23, the largest only Magnitude 2.5. This ongoing swarm is in the same area that had similar swarms in 2001 and 2012 and is likely just the same sort of thing taking place again. For more details and updates....

How big was that earthquake?

September 24, 2015

by Steve Malone

Determining an earthquake's size seems to often result in different and inconsistent estimates. The "Magnitude" of an earthquake can be determined by several different methods, all of which should have some relationship to one another and, at least be consistent one earthquake to another. Unfortunately that's often not the case. PNSN seismologists spend lots of time estimating (measuring and calculating) earthquake magnitudes and end up discussing (arguing over) different techniques and complaining (whining) about inconsistencies and criticizing (belittling) certain results. Recently some effort is being made to try and refine (improve) our standard, routine ways of determining magnitude. We are starting to upgrade our published catalog with these "improved" magnitude estimates so you may see these estimates change from what was in the catalog before. Don't worry. The earthquakes have not changed, just our estimate of how big they are. For the gory details of how this is being done......

Summer rockfall time, yet again

August 21, 2015

by Steve Malone

With hot dry weather it is not surprising that the seismic records for volcano stations show lots of signals consistent with rockfall/avalanches and other exotic seismic events. In fact it is a bit of a surprise that we have not seen more and bigger such events this summer........ so far. Recent activity at Mount Rainier has included a debris flow (probably related to a jökulhlaup) and a moderate sized rockfall from high on the southwest side of the volcano. For some of the seismic details.....

Why earthquakes disappear

May 31, 2015

by Renate Hartog

Earthquakes have been appearing and disappearing from the U.S.G.S. webpages, this blog explains why.

PNW Earthquake Early Warning prototype goes live

February 18, 2015

by Steve Malone

Earthquake Early Warning (EEW) is now officially working for the Pacific Northwest (Washington and Oregon) in the same way it has in California for the past two years. It even got tested the first night in operations and worked...sort of. A workshop hosted by the PNSN at the University of Washington on Feb 17 introduced the topic and featured software to a group of about forty invited participants. For a few details on the workshop and the system's first live test......
The Seattle Seahawks' win over the Green Bay Packers in over time ended up so exciting that many of us serious scientists forgot to be serious and analyze the seismograms. Yikes! What a crazy ending. In fact, most of the game was seismically quiet (and disheartening for Seahawk fans), but the final half hour produced several seismic events that challenges the original "Beast Quake" for seismic supremacy. For our semi-scientific analysis......

Panther versus Seahawk Game Analysis

January 11, 2015

by Steve Malone

Both the PNSN experiment and the Seahawks were successful Saturday evening. Both got off to a slow start. The PNSN QuickShake display had several bad dropouts during the first half and at half-time the Seahawks were only ahead by four points. When working properly QuickShake provided us with "early Warning" of a successful play that would show up on TV a few seconds later. None of the signals compared to the size of those during the original "Beast Quake" of 2011 but some interesting patterns were seen. For more detailed analysis......
Last year the PNSN used the vibrations generated by enthusiastic Seahawk fans at CenturyLink Field to test instruments, data acquisition and web based displays. Some might say the seismic monitoring inspired fans to greater cheering resulting in the Seahawk's successful Super Bowl run. With new instruments recently acquired and improved data processing and display techniques developed we are again looking for somewhere to test them. With the Seahawks again in the playoffs with home field advantage why not watch/help them again? For the details.....