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From tsunami wreckage in Japan, sobering lessons for California

May 20, 2011

Category: A Closer Look

Locomotive at Minimi Sanriku pushed 8 meters off tracks and toppled over, crushing commemorative tsunami stones in the process.

CSU geologist shares ‘recon’ in blog, photos

For the fourth time in less than two years, Lori Dengler has crossed the Pacific or the equator – or both – to explore in the wake of a devastating tsunami. She goes in search of scientific data and anecdotal evidence that will improve community preparedness for the next tsunami – whenever, wherever it hits.

Dengler, a Humboldt State geology professor oft-honored for tsunami awareness and earthquake-safety, just returned from a 10-day reconnaissance trip to Japan. As part of a contingent sponsored by the Earthquake Engineering Research Institute, she visited several cities that had been hit hard March 11 by the Tohoku-oki earthquake (or Great East Japan earthquake in its English translation), and by the fast-rising waters that quickly followed.

(She was among several CSU faculty who provided expertise – in the form of aid, advice and analysis – to benefit both Japan and California. Read the news story here.  Click here for other tsunami posts in Science & the CSU.  Mouse over photos for Dengler’s captions; click to enlarge them. For a gallery with 93 of Dengler’s reconnaissance photos from the trip to Japan, click here. )

Dengler describes her trip in a series of blog posts at the Redwood Coast Tsunami Work Group’s site: http://www.humboldt.edu/rctwg/blog. A “wrap-up” post will come soon. (Update: Click here for a report on her  “Japan Reconnaissance” wrap-up.)  Chronological excerpts follow below. First, from Day 7, this one explains why she goes there:

The purpose of reconnaissance trips is to get a quick overview of the issues in an event; and the process begins with small slices of what happened based on what we see, read, and who we talk to. Gradually a picture emerges that (I hope) comes close to the truth. But some of the early hypotheses may turn out to be in error or downright wrong.

The older woman returned for the first time to the Natori City area where her house had been. The only reason she survived was because she was shopping with her daughter that day.Numerous Japanese researchers are working on many aspects of the event and other international teams are here or will be headed to Japan soon. We share our ideas, debate issues, publish results and by a year from now, I expect there will be pretty clear consensus on the most important lessons from this event. But right now, data is still being gathered, and the situation is still fluid.

It’s one of the aspects of reconnaissance efforts that I find most stimulating – the scientific process in action and in overdrive….

A 5.1 aftershock gave us a little rattle around 3:30 AM. Hard to get back to sleep afterwards.

For the full posts from Japan (and dispatches from previous trips to Samoa, Chile and New Zealand), visit www.humboldt.edu/rctwg/blog.

Excerpts from Lori Dengler’s “Japan Reconnaissance”

Day 1 (April 29 – 30, 2011)

A long day in transit…

Day 2 (May 1, 2011)

One report summarizes the demographics of the victims. 92% are attributed to the tsunami, 4.5% to falling objects and structural failures, and the remainder due to fire. This is based only on bodies recovered – assuming all the missing are attributed to the tsunami, the tsunami victims increase to 97%. If there had been no tsunami, the casualties would have been less than 700….

Day 3 (May 2, 2011)

…We wanted to check out the fate of a grove of pine trees that had been planted about 15 years ago as a “tsunami forest”. Some scientists have argued that a sufficiently large grove of trees can dissipate tsunami energy. Unfortunately this grove didn’t have a chance. Most of the trees had been neatly snapped about a foot above the ground and now were mere indicators of the flow direction….The people were helpful and kind, and this family invited us in for tea (Dengler at right).

Day 4 (May 3, 2011)

The day began nearly as yesterday ended – with a low rumble followed 9 seconds later by slightly sharper swaying. Another aftershock. The day was focused on the people caught up in the tsunami and the decisions they made that contributed to their surviving. We started back at the Sendai Airport, this time going inside to talk with the people who had been there on March 11….

Day 5 (May 4, 2011)

…Then out to the hardest hit area of Yuriage – the extremely flat land within a half-mile of the coast. It also provided our first (and so far only) contact with police attempting to control access. The scale of the event is so large, there are so many ways to access the area, and personnel are stretched so thin that it would be very difficult to establish effective roadblocks. This was the most devastated area we’ve seen yet. Water heights in this region exceeded 30 feet and more than 1000 people died….

Day 6 (May 5, 2011)

…We finished the day with a quick tour out to the tip of the peninsula that separates Mastushima Bay from the Pacific Ocean. We chose a bad time of day to do the drive – 4 PM when all of the dump trucks and other heavy equipment were heading home for the end of the day….The contrast between the impacts on the Pacific side and the Bay were remarkable. On the Pacific, communities were obliterated. On the Bay, the main impacts were from liquefaction and the tsunami was relatively negligible.

Day 7 (May 6, 2011)

The Disaster Prevention Department Minami Sanriku town headquarters. At least twenty people died in this building...Note the hills in the background where they all could have easily walked to.…Last stop of the day was Minami Sanriku, a city noted for its tsunami preparedness efforts.… A particularly tragic story played out at the City’s Disaster Prevention Center (in Minami Sanriku), and a designated evacuation place. Keri Luna, a city official kept at the microphone announcing to the public that a tsunami was coming. Until she was finally overwhelmed. Of the 30 people on the fourth floor of the building, only 10 survived. Her body was found only a few days ago. Perhaps the saddest part of the story is that the building is only a five-minute walk from high ground; and if everyone had headed to the hill instead of the building, they all would have survived.

Day 8 (May 7, 2011)

How does one describe scenes of devastation day after day in a way that is not numbing? Today was Kessenuma near the northern edge of Miyagi Prefecture and Rikuzen-Takata in southern Iwate. Both of these cities were hit very hard with water heights over 5 stories high. As one approaches Kessenuma from inland, it looks very normal. The higher land in the outskirts is filled with shops and cars and people going about their business. The steady stream of military vehicles going in and out is an indication that things are not normal. The western end of the port area wasn’t so badly hit – although boats keep appearing in odd places and many of them are partially blackened by fires. As we head east, the situation quickly deteriorates and the alien landscape of debris, bombed out shells of buildings, and really bad smells come over us. Driving is a challenge….

…The big question now in cities like Kessenuma and Rikuzen-Takata is how to rebuild. It’s clear from Japanese television that there is pressure from some experts to rebuild the sea walls – just higher and larger. There will certainly be discussions about zoning and land-use planning….

Day 9 (May 8, 2011)

… He wanted to get his wallet and other personal belongings. His wife and daughter begged him not to go (back to his house), but he went Beautiful flowers in east Matsushima - just outside of the inundation zone.anyway. He was also stopped by the first tsunami surges before he arrived, and by driving very fast, was able to escape. We have heard this story now too many times – the earthquake was a trigger. Not the trigger to head to higher ground, but to go from a safe area and drive back into a hazard zone to get a loved one or to rescue possessions. We’ve only talked to the ones who escaped. My guess is that many of the victims did the same thing – they just weren’t as lucky….

Day 10 (May 9, 2011)

…We also meet with Masahiro Yamamoto, the Senior Advisor to the Intergovernmental Oceanographic Commission of UNESCO…. A lot has changed in the tsunami field since 1998 – technology and tools, scope, and involvement of many more disciplines.

….One of the biggest challenges I have found in post-event reconnaissance is distilling the information and getting reports written in a timely way…. As soon as I return­­­, I’ll be inundated…. I want to get a draft report done today while everything is still fresh in my mind and I still understand what my field notes refer to.

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