Lahar Detection System Developments at Mount Rainier

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Detailed Description

The video describes USGS efforts to improve lahar (mudflow) monitoring at Mount Rainier, an ice-clad volcano in Washington State with potential for dangerous volcanic mudflows. The presentation was given to colleagues in the US and in Ecuador by Andy Lockhart. Andy is a geophysicist with the the USGS/USAID Volcano Disaster Assistance Program, and he has worked to reduce the risk from lahars at many volcanoes worldwide. Warning systems at Mount Rainier are being developed with knowledge gained in other countries, including Colombia, Ecuador, and Guatemala.
 

Details

Date Taken:

Length: 00:20:22

Location Taken: Mount Rainier, WA, US

Video Credits

USAID Fuego lahar video by Martin (Rowdy) LaFevers
 

Transcript

Andy:    Well, I thought I would talk today about some updates on

Andy:    the lahar detection system working there at CVO and this is basically work in progress.

Andy:    Here is Mount Rainier in the background of the picture,

Andy:    the foreground is the Port of Tacoma,

Andy:    which is the mouth of the Puyallup River or the Puyallup

Andy:    drains the west flank of Mount Rainier.

Andy:    This is the lahar hazard map of Rainier.

Andy:    This is where the picture on the previous slide was taken from,

Andy:    looking southeast towards Mount Rainier up the Puyallup River valley.

Andy:    The other valleys on Rainier are also laharagenic ,

Andy:    we've got the Nisqually,

Andy:    Cowlitz, the White River,

Andy:    and the Carbon River.

Andy:    The Carbon River flows into the Puyallup River at about the town of Orting.

Andy:    This is Orting right here,

Andy:    and it sits on a layer of Rainier's,

Andy:    lahar and flood deposits among which is the Electron.

Andy:    They've been a number of

Andy:    eruption related lahars at Mount Rainier in the last 10,000 years,

Andy:    but the Electron 500 years ago,

Andy:    which had a volume of maybe 250 million cubic meters,

Andy:    left about three meters of material here at Orting.

Andy:    The problem with the Electron was it appears to have been sourced from

Andy:    a landslide up here on the upper west flank of Mount Rainier,

Andy:    unassociated with any volcanic activity.

Andy:    There's a possibility that this had no precursors.

Andy:    On the left is

Andy:    a slope stability map done by Mark Reid of the summit area of Mount Rainier.

Andy:    This red zone is the Summit Sunset Amphitheater,

Andy:    which sourced the Electron mudflow.

Andy:    Here's what it looks like from the ground.

Andy:    According to Dick Iverson,

Andy:    there's still enough material up here to do it again.

Andy:    This is what a 250,

Andy:    300 million cubic meter lahar looks like.

Andy:    This was the November 2008 lahar off of Huila in Colombia down the Rio Paez.

Andy:    This would have reached Orting in 50-60 minutes given its velocity.

Andy:    Here are school children practicing an evacuation from

Andy:    their school in Orting on a bridge across the Puyallup river.

Andy:    They're heading for the safety of the elevated areas on the south of

Andy:    town and it takes them about 45 minutes to walk from school to these safe areas,

Andy:    They practice this every year.

Andy:    We put this automated lahar detection system on Mount Rainier in 1998.

Andy:    Specifically, for giving Orting enough time to evacuate and we

Andy:    estimated that we could provide them somewhere between

Andy:    40 and 50 minutes before a lahar would hit that bridge.

Andy:    We're replacing that system, which had been based on AFMs, with broadbands.

Andy:    The new detection algorithm is the same as the one that we implemented in 1998.

Andy:    Instead of AFMs, we're using RSAM from the broadbands to detect

Andy:    a lahar and tripwires to determine if the lahar might be big enough to reach Orting.

Andy:    For that, we're using

Andy:    the standard LAHARZ constitutive equations that

Andy:    relate lahar volume with planimetric area,

Andy:    with cross sectional area,

Andy:    which we can measure with a tripwire.

Andy:    Here are some of the LAHARZ runs down

Andy:    the real Puyallup to the south and the Carbon River to the north.

Andy:    This is the town of Orting here.

Andy:    The pink zone is a 250 million cubic meter lahar,

Andy:    which represents the extent of an Electron size lahar.

Andy:    The red is a 40 million cubic meter lahar,

Andy:    which is about the size of the smallest lahar which would reach Orting.

Andy:    Now we'll look at our sensor array down here.

Andy:    Here's our sensor array,

Andy:    we have five stations.

Andy:    Two of them are high and above the levels of any anticipated lahars,

Andy:    three of them are dead-men tripwires,

Andy:    which are just within the reach of a 40 million cubic meter lahar.

Andy:    In our automated detection system,

Andy:    we have the following schema: four of the five stations must be operational,

Andy:    all the operational stations must register

Andy:    constant seismicity during this period of detection,

Andy:    and all of the operational dead-men stations or

Andy:    tripwires must either break a tripwire or stop transmitting.

Andy:    So this is our standard configuration.

Andy:    We have a box, we have a seismometer where we used to have an AFM,

Andy:    and we have a cable down here wrapped around a tree for our tripwire.

Andy:    The tree is just below the level of a 40 million cubic meter lahar.

Andy:    The Puyallup river represented down here at the bottom of the valley.

Andy:    So replacing the system.

Andy:    Lahar detection now is a priority at CVO.

Andy:    We're doing this with funding following

Andy:    a tragic landslide in the North of the state here several years ago.

Andy:    So CVO has a powerful team of seismologists and engineers working on this.

Andy:    We've got Wes Thelen and Kate Alstadt who

Andy:    are leading the scientific development along seismic and infrasonic lines.

Andy:    Rebecca Kramer, who's leading the field engineering effort,

Andy:    and Ben Pauk, who's doing all the admin wrangling.

Andy:    Chris Lockett who's leading the programming.

Andy:    You folks will remember Chris Lockett from,

Andy:    I think it was 2016 or 2018 when we were down there.

Andy:    Seth Moran, and I are also involved.

Andy:    So this is Rebecca standing here.

Andy:    This is the station design that she produced for the lahar stations,

Andy:    and this is the network.

Andy:    Now there have been many people working on the network design,

Andy:    but Rebecca is heading up the effort.

Andy:    You've got Mount Rainier here.

Andy:    The existing stations from the regional network are shown in yellow.

Andy:    There are a few of them.

Andy:    The proposed stations are in red.

Andy:    Those are mostly within

Andy:    Rainier National Park and require an extensive permitting process.

Andy:    The blue stations are stations that have already been installed as part

Andy:    of the upgrade of the lahar detection system.

Andy:    These are our current tripwire stations.

Andy:    They are at the same locations basically as the tripwire stations from the 1998 system,

Andy:    because that's as far upstream as we can get them and still have the system function.

Andy:    We have taken the higher stations and moved, Byson,

Andy:    he's in charge of the lahar detection software design,

Andy:    the associated IT system design,

Andy:    and he's a competent field hand.

Andy:    This is one of the screens from the OPC configuration software,

Andy:    a few of you will recognize this.

Andy:    This is the tool that Chris is using to replace the 1998 software.

Andy:    It is similar to what you have at Cotopaxi ,

Andy:    the OPC system that you have down there.

Andy:    He's also working on

Andy:    a simple and self-explanatory interface for the emergency managers at Pierce County,

Andy:    in the state of Washington,

Andy:    as well as real-time messaging and an interface for a USGS duty officer.

Andy:    But once he's done with the upgrade of the automated lahar detection system,

Andy:    he's going to turn his efforts to working on a more generalized detection or

Andy:    alarming package that will on based on Earthworm and not OBC.

Andy:    So this is Wes Thelen,

Andy:    down here. He's a seismologist.

Andy:    He's been working on,

Andy:    among other things, seismic amplitude source locations.

Andy:    This is some work that he did from locating

Andy:    a small debris flow that we had at Rainier last year.

Andy:    One of the advantages of doing this work at Rainier is

Andy:    that there are a large number of debris flows and

Andy:    small melt events almost on an annual basis that can be used to

Andy:    help develop these techniques with the instrumentation that we have installed,

Andy:    and show us where we might need to improve the network or our techniques.

Andy:    So here he's got an RSAM graph of one of the nearby stations.

Andy:    He's divided the hour long flow up into five different phases,

Andy:    and then located events from each of those phases on the side of the volcano.

Andy:    So this star here indicates where the lahar actually occurred.

Andy:    These three little red triangles are the stations,

Andy:    and the colored balloons are the locations from early to late within each phase.

Andy:    He's constrained these locations to lie along known stream valleys.

Andy:    Ideally, you would like to see these traversing from high

Andy:    on the volcano to lower on the volcano,

Andy:    and you would like to see them start where the actual lahar was.

Andy:    You can see that he's been successful in limiting them to

Andy:    the quadrant of the volcano that we

Andy:    are interested in knowing where things are coming down.

Andy:    So it's successful in

Andy:    telling us that things are coming down the Puyallup/Nisqually.

Andy:    But you can see that if there were more stations here,

Andy:    he'd be getting a better set of locations using this ASL technique.

Andy:    But it's pretty promising.

Andy:    With the same debris flow,

Andy:    he analyzed the infrasound taken from a three element array located down here.

Andy:    This is where that lahar was located,

Andy:    and these is where the back azimuths intersect

Andy:    streams of different events within this infrasound event.

Andy:    This is the iPensive display of the infra sound event.

Andy:    You can see the lahar,

Andy:    the debris flow occurring in this part of the graphic.

Andy:    This is a ten-minute long period,

Andy:    and so the Lahars is best represented here.

Andy:    This is probably an aircraft.

Andy:    It doesn't have anything to do with the Lahars.

Andy:    You can see the back azimuths come from 90° back.

Andy:    But you can see that it's a complicated problem.

Andy:    With one array, you're not able get much

Andy:    of a fix on this lahar even though you can detect it.

Andy:    So there's clearly more work to be done here.

Andy:    The other thing that Wes is working on is designing

Andy:    a decision matrix to help a duty scientists to quickly

Andy:    identify whether a lahar

Andy:    is happening or whether the information is providing a false alarm.

Andy:    This is Kate Allstadt.

Andy:    She's also a seismologist.

Andy:    Here, she is using a hammer as a signal source to

Andy:    generate Empirical Green's Function for a beam forming experiment,

Andy:    which she's doing at the USGS flume.

Andy:    This is a map of the flume.

Andy:    It's about a 100-120 meters long.

Andy:    The circles indicate two seismic arrays that she has placed here,

Andy:    and I want you to remember these for the subsequent slide.

Andy:    This is array C, and this is an array B.

Andy:    So here is the same flume.

Andy:    We're going to run a video of this here in a minute.

Andy:    The experiment is running eight cubic meters of sand and gravel,

Andy:    and cobbles down this flume.

Andy:    Twenty meters long. These circles indicate two seismic arrays that she has placed here.

Andy:    I want you to remember these for the subsequent slide,

Andy:    this is array C and this is array B.

Andy:    So here is the same flume. We're going to run a video of this here in a minute.

Andy:    The experiment is running

Andy:    eight cubic meters of sand and gravel and cobbles down this flume.

Andy:    These are those two arrays.

Andy:    This is the C array, which is off to this side,

Andy:    and the B array,

Andy:    which is off to this side.

Andy:    The C array is set at a lower frequency level.

Andy:    Time from 0 up to 20 seconds,

Andy:    and the vertical axis is distance of the material down the flume.

Andy:    So here, I want to explain these lines.

Andy:    This heavy line is the flow,

Andy:    and these dots are where the beamforming algorithm places the event.

Andy:    So what she finds is that there is a blind zone for

Andy:    the B array for the distance below about 50 meters,

Andy:    but the C array tracks the flow fairly well.

Andy:    This is a point where the flow stalls.

Andy:    This is where the surge overtakes the front,

Andy:    and beyond that is a chain of surges.

Andy:    Now, I want you to watch here.

Andy:    We're going to run a video.

Andy:    This red arrow is going to indicate these points where

Andy:    the beam forming from the C array is detecting events.

Andy:    The yellow is where the B array is detecting these events.

Andy:    Now, here we go.

Andy:    That black dot is the front of the flow and the red dot is the center of

Andy:    mass.Time in the flow is shown up here.

Andy:    So you can see that this C array with

Andy:    the higher frequencies is tracking the flow much better than the B array.

Andy:    Now, we've gotten up into a point where the flow is basically

Andy:    happened and they're just pointing at noise.

Andy:    The other thing that she's looking at is the response of tilt meters to flows.

Andy:    We installed a couple of tilt meters along the side of the flume as an experiment,

Andy:    and she noted that there is a tilt response to the passage of a bulk of material.

Andy:    She and a student are currently evaluating these data.

Andy:    This is Ben Pauk.

Andy:    He is in charge of making everything go.

Andy:    He's doing the permitting and admin work,

Andy:    the budgeting, the field planning, logistics, helicopter management.

Andy:    He's also a competent field hand.

Andy:    Here he is on snowshoes on the top of Mount St. Helens.

Andy:    The other thing that's going on here that isn't directly associated with

Andy:    the Rainier Project is

Andy:    the development of the D-Claw software by David George and Dick Iverson.

Andy:    Dick just retired from CVO.

Andy:    So D-Claw provides a useful tool for seamlessly integrating

Andy:    a simulation of debris avalanches and lahars from the initial event down to deposition.

Andy:    In addition to all CVO's work,

Andy:    VDAP  has been doing some work and we're doing some lahar monitoring in

Andy:    Guatemala at Fuego following the June 3rd, 2018 event.

Andy:    This is a video of a lahar coming down the Rio Cenizas that was taken by Rowdy.

Andy:    I want you to notice this water pipe that is broken here by the lahar. Here it is.

Andy:    They're dredging it out for the next lahar.

Andy:    So this water pipe is three or maybe four meters above the level of the stream here.

Andy:    Lahar is here, they're 3-4 meters deep.

Andy:    One of the things that we found working at Fuego at these lahars is that the S grams (seismograms) give

Andy:    a really good instant indicator that the lahar is occurring without even pointing at it.

Andy:    You can see that there are three lahars represented in this day-long S gram.

Andy:    We're going to look at this lower one.

Andy:    This is what it looks like on Swarm.

Andy:    You can see the seismic signal associated with

Andy:    this lahar and the spectra that Swarm shows.

Andy:    This is a webcam that we have located at this site.

Andy:    This is the Rio Cenizas.

Andy:    It's raining hard, so it looks a little fuzzy.

Andy:    This is at 14:20,

Andy:    at about this point in the seismic trace.

Andy:    Ten minutes later at 14:30, you can see there's a lahar occupying a valley.

Andy:    The front of the lahar has already passed.

Andy:    Now, we're at the point pretty close to the maximum seismicity from this flowage event.

Andy:    However, we have a six-element infrasound array at this location and and it sees nothing.

Andy:    This was predicted by Mario Ruiz

Andy:    last year when I was in Ecuador.

Andy:    So clearly there is more work to be done.

Andy:    Wes' work on Rainier is encouraging but that is where we are today.

Andy:    Thank you very much.