LiDAR of Mount Saint Helens

It is not candle wax - LiDAR of southeast flank of Mount Saint Helens

The UGS has a large pdf file available on line of Mount Saint Helens HERE. The south flank of the mountain appears so constructive compared to the destructive north half of the mountain. I enjoyed a virtual tour zipping around the mountain. Lava flows on top of lava flows.

Snow Fences in Whatcom County

Snow fences northwest of Lynden, Washington

I had a field trip northwest of Lynden, Washington yesterday and spotted these snow fences in a pasture and on a field of corn stubble. It is the only snow fence I have ever seen in western Washington. Washington State weather geeks are well aware that when cold Arctic air enters western Washington there are very strong northeast winds that blow across Whatcom County. A weather joke is that Seattle TV stations always send their reporters north of Bellingham when an Arctic front is blowing across Whatcom County so they can stand in a the freezing wind and pronounce cold temperatures are on the way to Seattle. 

Snow covered pasture, corn stubble or hay fields do little to stop blowing snow. The farmland around Lynden gets huge drifts with miles of treeless fields. A few homes are located across the road from this particular field and hence the snow fences to stop drifts of snow piling up around the houses. 

A Few Notes on Bellingham's Former Coal Mines

Walsh and Logan (1989) showing two of the mines underlying

Bellingham with the downtown area on the lower right. 

A much bigger mine underlies the northwest portion of the city. 

I previously did a write up on investigating the Sehome mine beneath downtown Bellingham  patch-over-bellinghams-void. Every now and again the coal mine issues in Bellingham come up. Last week I was asked three time what I might know. The last question was regarding a property that the City of Bellingham owns along Cornwall Avenue that they may be selling. I am fairly sure that the site was investigated for the potential that a mine was under the site using a drill rig several years ago. I have heard second hand that the mine did not extend under the site, but I have never seen the drilling records. The Sehome mine has had subsidence problems in the past and reports of new subsidence would not be a huge surprise.

A property developer asked me last week about potential problems from the Bellingham Mine underlying northwest Bellingham. This mine was evaluated by Tetra Tech in the 1984. The mine had fairly good records as to shafts and drifts. No retreat mining took place. That is they left coal pillars to support the mined areas.

Collapses can and will take place as the voids left by the mine eventually collapse. The question is how will that impact the surface and structures on the surface. Knowing that areas of coal were left (pillars) and the width and height of voids, rock type, depth to voids, angle of the void, thickness of overlying bedrock, thickness properties of unconsolidated materials over the bedrock, a mathematical model can be used to calculate how the surface may be impacted. Various models have been developed based on areas where mine collapse have taken place. I used a model developed from collapses in Poland for a mine subsidence project several years ago.

Tetra Tech (1984) evaluated the Bellingham Mine and did produce a map of areas where there was a low risk of subsidence - mostly along limited areas near Northwest Drive not far from the former mine entrance where the mine is shallower.

For the Bellingham Mine the biggest risk areas are associated with ventilation shafts and locations where the coal "daylighted" into unconsolidated (non rock) sediments. In these locations the settlement models do not work so well because the loose over burden sediments can pipe (flow) into the mine voids. The Bellingham Mine records were good enough that the potential daylight areas can be identified and I would say in those areas there is a very modest risk to higher risk dependent on the depth to the mine. As for vents, they were not well mapped. I have heard second hand as did Tetra Tech of vent collapses associated with the mine. These could have been vents or piping of sediment into daylighted areas. I did see a bit of a low spot on a property that I speculated may have been a settlement feature associated with a ventalation shaft.

My company does environmental due diligence investigations, and while mine subsidence is outside the scope of that work we will say something if we think there could be an issue. There are other areas around Washington State where mining has taken place and subsidence from old mines has taken place particularly in the eastern King County area east of Seattle such as near the aptly named Black Diamond.

One final note, there is a national insurance program for damages caused by coal mine subsidence. The program is funded by a tax on coal. But a subsidence must take place first. It is generally a reactive versus proactive program.

Tsunami Policy in Washington State: Grays Harbor County, One Example

As a follow up on my long post regarding policy for tsunamis in Washington State yesterday I have a couple of quick adds. As I have noted many times on this blog, I try to be neutral. This blog ends on a decidedly non neutral note.

First:  Lyle alerted me to Callan's post on the AGU page regarding coastal subsidence along the west coast of Japan from the earthquake mountainbeltway/new-gps-vectors/. The critical part is that the Japan quake matches reasonably well with the evidence Brian Atwater has found on Washington State's outer coast.

Second: I looked up one local critical areas code for our outer coast, Grays Harbor County. Tsunami is not in the definitions section and there is no mention of tsunamis in the geologic hazard section. There also is no mention of alluvial fan hazards. Nor is there mention of coastal subsidence or any other seismic hazard beyond reference to the designing building to meet the uniform building code. Grays Harbor does have flood regulations that take into account high water from the ocean utilizing FEMA flood maps, but the tsunami hazard dwarfs the 500 year flood levels and the FEMA flood maps make no mention of tsunamis.

Google Earth view of Grays Harbor County on Washington State's outer coast

Grays Harbor County is predominantly heavily forested low mountains and hills. Most of the populations lives on the coast, along the shores of Grays Harbor, the drowned lower valley of the Chehalis River, and along the Chehalis River valley. Evidence of past tsunamis can be observed at many coastal estuaries along the shoreline including the spectacular ghost forest along the Copalis River in the northern part of the county SEE HERE. 

Most of the developed areas in Grays Harbor County developed well before there was any understanding of the seismic risk on the Washington State coast. Settlement by Europeans and Americans began in the early 1800s with settlement taking place along the inner shorelines of the bays. If local First Nations peoples said anything about giant waves, the stories may have been difficult to believe. As geologists began to understand plate tectonics and seismic events along convergent plate boundaries, the lack of earthquakes on the Washington coast became an interesting riddle. Brian Atwater postulated that there should be evidence of past quakes along the Washington coast and went to Grays Harbor County and found the evidence in the 1980s. Subsequent studies along the coasts of British Columbia and Oregon have built on our understanding of the seismic risk.

While Grays Harbor has yet to recognize tsunamis in the development regulations, the county emergency planners have been working hard to plan for the coming earthquake and tsunami event. The communities in Grays Harbor are well signed with tsunami evacuation route signs, tsunami warning sirens are more prominent than cell phone towers and there are routine community events. People in Grays Harbor are well aware of the risk.  

In addition to evacuation routes, Grays Harbor County as well as areas to the south in Pacific County have begun thinking about tsunami platforms as some areas will be difficult to evacuate within the short time between the big quake and the tsunami arrival. Elevated areas within the dunes on the sand spits may provide enough height along with a deeply bedded platform to protect people. And the platforms may provide great views for birders and other tourists. 

  

Tsnuami Platform. Photo courtesy ITC

Grays Harbor County has made great progress in emergency planning. People living there know what to expect and are as well prepared as anyone. But in terms of land-use planning within the county codes, tsunami hazards are note yet recognized. The Tsunami Hazard Map of the Southern Washington Coast (Walsh and others, 2000) http://www.dnr.wa.gov/Publications/ger_gm49_tsunami_hazard_southern_coast.zip closes with the following "This means that, while modeling can be a useful tool to guide evacuation planning, it is not sufficient resolution to be useful for land-use planning." Walsh and others note that horizontal errors of up to 165 feet and vertical areas on the order of 7 to 20 feet may be present in the model.

This problem with dead on accurate maps for planning purposes ought not to prevent some level of development planning. Look at the evacuation maps carefully and it should be noted that fire stations and police stations are located with the tsunami hazard area. Our federal, state and local governments invest large sums of money in public buildings. Land-use planning should at a minimum include the tsunami hazard risk for locating key government facilities as well as hospitals. And there is no reason not consider other types of development as well. Should nursing homes or child care facilities be developed with tsunami hazard zones? Circumstances will vary from community to community in how these difficult decisions should be made and how the risks posed will be dealt with. There is much to be learned from the Sendai, Japan earthquake and not only emergency planners but land-use planners should be looking closely at what worked and did not work in Japan. And we will never have dead on accurate maps of tsunamis, but we should have a pretty reasonable idea where the tsunami danger zones are based on the maps we have so far.  

Great Britain Prime Minister David Cameron said of the quake in Japan "a terrible reminder of the the power of nature”.  Too frequently events like this are viewed in that manner. From the perspective of living on the Cascadia subduction zone western Washington residents should be thinking this about the Japan quake “a terrible reminder of the cost of not planning well for an obvious risk.” From the dragging out the replacement of the Seattle viaduct to huge government subsidized development projects proposed within known tsunami hazard zones, Washington State and communities within Washington State are ignoring an obvious hazard at potential great cost in property, investment and lives.

Policy Considerations for Washington State Post Japan Quake and Tsunami

A year ago last January I did some exploring of the estuaries along the southwest Washington coast. At one point I stopped paddling of my boat and contemplated a pile of exposed rounded rocks exposed in the bank of the estuary. I was trying to figure out how the currents must have flowed to deposit a small area of grapefruit sized rocks in an otherwise muddy area. A sand layer from the tsunami deposit that I was tracing covered the rocks. I continued my paddle perplexed. Then I remembered we are living in the Anthropocene. The rocks were a fire pit buried by the great wave that swept inland over southwest Washington late one cold January night night in 1700. We need to get ready. 

Tsunami deposit exposed in estuary bank

Dead tree from subsidence cause by the great 1700 quake.

There is so much to learn from the most recent earthquake in Japan. Certainly nuclear fission reactor design and operators are having a learning experience. Not one that could be called remotely pleasant and alas for some very dangerous with signs that the reactor containment may be partially compromised at last update. The policy implications for this will be interesting to follow and global.  


In my own mind I have been developing comparisons between Washington State and northern Japan in terms of how does this seismic event relates to western Washington's tectonic situation. It is worth making some comparisons regarding the event in Japan and what could happen in Western Washington.

Tectonically western Washington and Japan are fairly similar. Both Japan and Washington are located on a convergent plate boundary with ocean floor plate subducting under Japan and the same in Washington. The major tectonic structure is essentially a major thrust fault with the ocean floor sliding under Japan and Washington. These types of plate boundaries produce the biggest earthquakes. How are they different? The ocean plate subducting under Washington is much younger than the ocean plate subducting under Japan. This might make a bit of difference as to where earthquakes take place and how deep earthquakes will be but only in a general way. There are likely some secondary effects and seismic events within the subducting ocean plate and overriding continental plate due to this age of crust difference, but again those are details for seismic geologists and the story of a big subduction quake is the same.

Perhaps the biggest question for Washington State is the possibility of a major subduction quake located off shore or the possibility that the quake might take place beneath the land area along the coast. Distance to epicenters matter greatly. This last event in Japan was 80 kilometers off shore. It was a huge quake but at least some distance separated the quake from cities and homes. I have not read of any coastal subsidence or uplift along the coast of Japan from this event and am very interested if that took place. On Washington State's outer coast large quakes causing substantial coastal subsidence is evident all along the coast. Location and depth of quake epicenters matters greatly and this question is one of great interest for seismic folks.

The ocean plate subducting under Washington State is subducting at an angle such that lateral forces on the upper crust come into play. This is the case in parts of Japan as well, but in other areas the collision is more direct. In areas where the collision is at an angle there are strike slip faults, normal faults and blind thrust faults inland from the subduction fault and that is the case in Washington and in certain areas of Japan. At a localized level these faults are just as dangerous or depending on proximity substantially more dangerous. A major off set along the faults cutting across Bainbrige Island will give nearby land a jolt much greater than the subduction zone quake. 

The bottom line is that there is plenty of evidence that Washington State will have similar types of large earthquakes that have impacted Japan and in fact these types of quakes should be expected and planned for in Washington State. 

The tsunami impact in Japan is simply shocking. We know that tsunamis associated with great quakes have impacted the Washington coast. It is abundantly clear that large swaths of coastal lowland areas particularly on the outer coast are very vulnerable. This information is not new. First Nations peoples on the outer coast had many stories of a great wave. The last large quake in Washington State took place in 1700.  Furthermore the images from Indonesia and Chile have previously reinforced the understanding of the risk facing Washington State as well as Oregon and British Columbia. But with the images from Japan, a country that has known tsunamis for centuries and even measured and recorded and planned for tsunamis, Washington State should learn some lessons. 


Some steps for tsunami planning have begun. For example some state money was set aside for construction of tsunami shelters on the Long Beach Peninsula due to lack of natural safe locations being near by. Maps showing potential tsunami inundation have been developed based modeling the big quake. A careful look at what happened in Japan suggests that for areas without nearby safe high ground much more should be done. Warning systems have been built and signs pointing the way for escape have been installed. I am not sure of the status of the shelters on Long Beach, but it is abundantly clear that they are needed and there are likely other locations where these facilities will be needed as well.  

In one very important regard, Washington State has a distinct advantage over Japan. At this point in time a lot less people live in potential tsunami hazard areas in Washington State than in Japan. Substantial changes will be required in land use planning and infrastructure investment to prevent substantial increases in population within tsunami areas. 


From a land use planning perspective, all coastal counties and counties within the inland water areas should recognize tsunami areas as geologic hazard areas within existing critical areas ordinances that are required under the Washington State Growth Management Act. Clear guidance for recognizing this hazard and requirements for areas within this hazard should be developed by the State and the State needs to require that regulations for these areas are adopted and enforced at the local city and county level. Recognition of various circumstances will need to be considered. For example, towns have developed within the hazard area already. Oysterville and other small communities on the far outer coast will do very poorly when the tsunami arrives shortly after the great quake. Even small cities such as Aberdeen and Hoquium should have carefully thought through regulations and plans that require recognition and planning for a very destructive tsunami event that will happen.

A somewhat similar approach has been followed by counties in Washington State regarding volcanic hazards. However, because of a lack of specific state requirements some communities have developed geologic hazard regulations that are silent on the volcanic risk or have code language that will allow far too much development to extend into locations that will be destroyed. I an not advocating banning all development, but consideration of development scale and types should be considered and a rationale should be developed as to what will be allowed and what won't be allowed. I will give one example. Whatcom County has a volcanic hazard area and certain types of development are banned within those areas and policies for planning have been developed that recognize that these areas are at risk and development in these areas should be limited.

While arguments can be made about recurrence intervals of large scale volcanic or tsunami events not warranting any additional precautions or regulations, those arguments should be made only after watching a few videos of the tsunamis that swept inland along the Japanese coast last week.

A final policy issue is where infrastructure investment takes place. Clear state policies as well as local and federal policies should discourage investments that encourage development in dangerous tsunami hazard areas unless there are specific compelling reasons for the development with few alternatives such as shipping facilities.

People get ready. We do not want to leave people bewildered and confused on a dark winter night like the First Nations coastal communities in 1700. 

Liquefaction Clip from Chia City, Japan

Kat via a comment provided a great link by Brent Kooi, CNN reporter (thanks Kat). The tsunami clips have dominated the news but there is some other amazing footage. Kat asked if this sort of liquefaction could take place in reclaimed areas of Seattle. There are lots of liquefaction areas in Seattle reclaimed (fill on tide lands) areas as well as many other northwest cities. One of the reasons the Seattle viaduct needs to be replaced HERE. So watch this video and picture the viaduct supported by the soils seen in the video. Also note that at about 30 seconds into the video there is a view of a grass covered area and then a few seconds later another view. In the first view there is no water; in the second view there are puddles of water.

Earthquake and Tsunami in Japan - Early Thoughts

The Japan earthquake and tsunami is hard to take in. As a geologist who works on geologic hazards I want to learn what I can, but the issues raised by this quake extend well beyond a simple understanding of geology.  Large earthquakes are terrible events, but there is a lot to be learned. Geologists, geotechnical engineers, civil engineers, structural engineers and emergency responders all will study these events to try to learn lessons. I hope planners and those that make infrastructure funding decisions will learn as some lessons as well. Lots of lessons for Washington State as we live in a similar geologic setting.

As I digest things, I will write more later. This is an event that overwhelms a geo blogger. I noted a tremendous number of page views from last Friday's post indicating people want to know more, but I do have to work! Silver Fox provides a long list of sites to check HERE. Reuters, BBC, CNN and NY Times have done a commendable job.

A few early thoughts:

1) The areal footage of the tsunami waves was unprecedented as well as some on the ground footage. The images present a hard lesson but one that will be hard to ignore.

2) Large areas that were hit by the tsunami were far from high ground, required reaching high ground via driving and road routes to high ground were not direct. With less than half and hour to reach safety there was little time to escape and for some an impossible task. This takes us back to thought number 1 above. There is a lesson here that very much needs to be considered in Washington State in regards to planning.

3) The tsunami damage combined with the nuclear plant issues dwarf the more typical issues regarding earthquakes as far as building and infrastructure holding up to shaking. In looking at the tsunami wave footage, it appeared buildings were in good condition in general and bridges with wide spans built on alluvial material had withstood the shaking. I am sure there were failures, and where those failures took place and why will add to our ability to properly construct buildings and infrastructure to minimize death and injury.

4) The nuclear power plant issue is stunning. georneys.blogspot has an interview with her father, a nuclear engineer, that is nice cool headed alternative to the news and I must say very well done. But I suspect that this issue will have broad global impacts and have significant imapcts here in Washington State.

So a few early thoughts that I will write about at some future date - likely months from now!