Saturday, April 30, 2011

More imagery--Minami Sanriku and beyond -- and tsunami erosion

The oblique air photo above (by "yaozy"), available on Google Earth, shows dramatic tsunami scour features in the Minami Sanriku harbor. It also gives a better sense of the area I walked around in April of 2010. Finally I can faintly see the baseball diamond near the (destroyed) river gate, and get a sense of the tsunami erosion around the large apartment building at the shoreline, a building designated for vertical evacuation. I still don't know how many people used this building for evacuation, and if so, did they successfully get onto the roof because the upper floor was flooded.

I have been readjusting to life back in Seattle, trying to finish up several manuscripts that got pushed aside by the events of 11 March. These manuscripts deal with neotectonics and tsunami history of the Kamchatka Peninsula.

The other day, we were trying to imagine "life before Google Earth." I remember life before photocopy machines, let alone word processing! I was rereading a classic, early article by Minoura on a Kamchatka tsunami deposit, and wondering if we could relocate his sites. So much of Minoura-san's materials will have been destroyed by the earthquake in Sendai. I realized his work was not only before Google Earth and GIS, but probably done without GPS.... Though we had handheld GPS in our post-tsunami survey in Nicaragua in 1992, it wasn't working very well. Funny, there were two sets of maps -- the Nicaraguans had maps prepared by the Soviet Union for the Sandinista regime, and we from the U.S. had maps prepared by the U.S. Defense Mapping Agency, which said "destroy after using." The "KGB" maps were more accurate than the "CIA" maps.... Of course, air photos are still the best for on-the-ground location, though post-tsunami, things change. And some countries are not so enthusiastic about providing/ making public their air photos. How things are changing now with so much on the web.

Meanwhile (back to the present), thanks to Paleoseismicity:

for posting some good links, such as:
The title of this panorama project should be "japan-tsunami-panoramas" though.

From Google Earth, I found a newly acquired image of the harbor of Minami Sanriku that shows clearly severe tsunami erosional features, which by their looks are mostly from the outflow -- Bre MacInnes will be interested to see these. Part of her dissertation was about tsunami erosion, particularly by the 2006 (or 2007) central Kurils tsunamis.

Here is a before image of the Minami Sanriku harbor from June 2010:

and the same view from 6 April 2011:

and my rough attempt (I did not orthorectify the images) to outline before and after shorelines, as well as the scour ponds made by the tsunami:

OK, back to my manuscripts.

Thursday, April 14, 2011

Tohoku coast -- Focus on Survivors

It's hard sometimes to think about statistics when peoples' lives are involved, but I found the data below heartening. Despite the widespread devastation in these towns, preliminary data show that really, most people survived. Early statistics used the total population of these towns, but these data attempt to count only the part of the population that was in the inundated area.

The table is ordered from most to least casualities (= dead plus missing). I added the survivors columns, which therefore are ordered from least to most survivors, top to bottom. So the bad news comes first

Preliminary table of survivors within inundated region of Iwate, Miyagi and Fukushima prefectures*
Prefecture Township Population within the inundated area (a) Dead + Missing (b) % casualites (a)/(b)x100 Survivors % survivors
Iwate Otsuchi 7839 1616 20.6 6223 79.4
Iwate Rikuzen-Takada 13547 2459 18.2 11088 81.8
Miyagi Onagawa 8816 1504 17.1 7312 82.9
Miyagi Natori 12132 1873 15.4 10259 84.6
Iwate Kamaishi 9331 1306 14.0 8025 86.0
Miyagi Shiogama 173 23 13.3 150 86.7
Fukushima Minami-Souma 13919 1474 10.6 12445 89.4
Miyagi Yamamoto 9341 788 8.4 8553 91.6
Miyagi Minami-Sanriku 13306 1090 8.2 12216 91.8
Iwate Yamada 11721 911 7.8 10810 92.2
Miyagi Kesennuma 29648 2138 7.2 27510 92.8
Fukushima Namie 2749 186 6.8 2563 93.2
Miyagi Ishinomaki 102670 5520 5.4 97150 94.6
Miyagi Higashi-Matsushima 32993 1713 5.2 31280 94.8
Fukushima Souma 9227 408 4.4 8819 95.6
Iwate Miyako 24937 1083 4.3 23854 95.7
Iwate Tanohata 1075 38 3.5 1037 96.5
Iwate Ofunato 15500 494 3.2 15006 96.8
Fukushima Futaba 1061 32 3.0 1029 97.0
Fukushima Shinchi 4258 118 2.8 4140 97.2
Miyagi Iwanuma 7310 183 2.5 7127 97.5
Fukushima Okuma 1053 24 2.3 1029 97.7
Miyagi Watari 13186 284 2.2 12902 97.8
345792 25265 7.3 320527 92.7

Average survival rate within inundated area: 92.7%

Statistics Bureau & Director-General for Policy Planning of Ministry of Internal Affairs & Communications
released "Populations and Number of families within the Expected Inundation Areas" in Japanese.

Inundation areas are estimated by aerial and satellite photos; not the survey on site.
*The table prepared by Yamamoto, Masahiro (Jody B. added survivor columns).

Tuesday, April 5, 2011

Minami-Sanriku update

See my previous blog for more background on Minami-Sanriku.
Only some survive on top of the town disaster management center
Pictures: Shinichi Sato/AP

"Chilling new photographs show people desperately clinging to a mast on a roof as the Japanese tsunami destroys the building beneath them.

In the combination of three photos, taken by Shinichi Sato amidst the March 11 disaster, survivors cling to an antenna tower and handrails on the roof of the Minamisanriku Government Disaster Readiness Center in Minamisanriku, north-eastern Japan.

About 30 people fled to the roof of the three-storey building and climbed higher as the tsunami rushed in. Only nine people survived and about 20 were swept to their deaths."

A young female official who kept delivering the evacuation message to townspeople until the last moment has not been found. Tanioka says the story of her bravery and dedication is now nationally known.

Lensman braved tsunami

Wednesday, April 6, 2011

"MINAMISANRIKU, Miyagi Pref. (Kyodo) When the municipal disaster prevention building in Minamisanriku, Miyagi Prefecture, was engulfed by the tsunami on March 11, its officials clinging to the top of the structure, a local photographer captured the drama in a series of pictures.

The photos, made available by Shinichi Sato, show the three-story building completely submerged by the wall of water except for its antenna and rooftop fence, to which Mayor Jin Sato and nine other survivors from the office clung.

(Shinichi) Sato, 45, who ran a photo studio in his home until the tsunami hit, captured the scene from an elementary school overlooking the town.

'A tsunami will come,' he thought soon after the powerful earthquake struck. He first instructed his family to evacuate, then took his camera and drove to a hilly area where he could see the town below.

As Sato continued pressing the camera shutter, he was oddly calm and didn't feel terrified, he said. Sato is now photographing the recovery effort."

From a Rapid Damage Assessment and Need Survey

The report has high-resolution images from a number of the towns including and south of Minami-Sanriku. It is about 7 Mb and was provided to me by Tom Banse of Public Radio Olympia Bureau. Support public radio!

The report has high-resolution images from a number of the towns including and south of Minami-Sanriku. It is about 7 Mb and was provided to me by Tom Banse of Public Radio Olympia Bureau. Support public radio!