The Japanese Tohoku Earthquake and Tsunami of 11 March 2011

Rikuzentakata and Kesennuma used to be large fishing and industrial communities

Figure 1. Rikuzentakata on the day after the tsunami hit (part of Asia Air Survey's extensive coverage of tsunami damage - click the figure twice for maximum resolution). Compare satellite views in Google Earth of the city on 23 July 2010 (before) and 12 March 2011 after the town was struck by a 14-15 m tsunami. The human impact on Rikuzentakata City as at 18 April 2011 (IOC/UNESCO Bulletin 21) total land area = 232 km2, inundated area = 9 km2, depth of inundation: coastal area = 14-15 m (run up = 17 - 19 m), total population = 23,243, confirmed deaths = 1,347, missing = 822. For details see B. Rikuzentakata in Iwate Prefecture.

Figure 2. Kesennuma city the day after the tsunami (part of Asia Air Survey's extensive coverage of tsunami damage - click the figure twice for maximum resolution), showing the damage caused by the tsunami that peaked at 12 to 14 m in this area. The human impact on Kesennuma City as at 18 April 2011 (IOC/UNESCO Bulletin 21)
total land area = 333 km2, inundated area = 15 km2, depth of inundation: Koizumi Primary School = 16.06 m (run up); Akaushi, Motoyoshi = 22.2 m, total population = 73,239, confirmed deaths = 815, missing = 1,216. Four videos chart the progeression of tsunami's first wave through the city: Video 1 - outer port area (another witness from same location), Video 2 - river junction, Video 3 - commercial center, Video 4 - inner harbor. For details see C. Kesennuma in  Miyagi Prefecture.

The Japanese Tohoku Earthquake and Tsunami of 11 March 2011 is one of the worst disasters to affect a highly developed nation in a century or more. As will be demonstrated, it is also a disaster which has been documented to an unprecedented extent using a variety of visual and social media by those who lived through it. This web site collects and links many of these records to document to highlight how important it is for politicians, planners, managers and engineers to consider the potential impacts of rare but extreme events in their risk analysis, planning and design of public and private facilities and infrastructure.

Nearly two months after the disaster, Japan was still working just to measure the effects of the earthquake and tsunami. From the 2 May 2011 summary to the Asia Disaster Relief Center, the statistics from the Major Disaster Management Headquarters 2011/05/02 are summarized here. The numbers below are from one of a succession of reports summarizing the latest/most complete information available, and it can be seen from these summaries that the numbers are still fluctuating on a daily and weekly basis as more and presumably more accurate counts become available. One of the difficulties in establishing these numbers is that the records of many village, town and city administrations were lost along with the destruction of their buildings and deaths of administrators.


 Personal Injury
 Material Damage
 Confirmed dead:    14,723
 Fires:                                  345
 Missing:           10,807
 Totally collapsed buildings:         78,841
 Injured:            5,278
 Half collapsed buildings:            29,564
 No. of evacuees:  126,066
 Part collapsed buildings:           229,815
   Inundation above floor level:         4,213
   Inundation below floor level:         4,510
   Totally and half burned buildings:      260
   Uninhabitable houses:                25,272


These statistics neglect the costs and trauma from the shut down of a significant fraction of Japan's electricity generating capacity, tsunami damage to significant parts of Japan's manufacturing and transport infrastructure, agricultural, and fishing industries, all topped off by the effective destruction of four nuclear reactors and the forced evacuation of a large area because of the risks from nuclear fallout from highly radioactive nuclear fuel burning in the open air.

Japan is a country long used to earthquakes and tsunamis. As can clearly be seen from space via Google Eart
h images, virtually every village, town and city along the Pacific Coast had a variety of tsunami defenses including breakwaters and town seawalls. Even though the Tohoku earthquake was the strongest to hit Japan for more than a century, it is clear that the structured environment was well able to resist earthquake damage. For example, in the video records of the tsunami arrival, even in the closest locations to the epicenter, prior to the arrival of the tsunami there is very little evidence of structural damage. The physical robustness and earthquake resistance of many buildings is shown by the number that remain intact even as they are torn off their foundations, churned around and smashed together by the tsunami floods before eventually being broken into match sticks by the overwhelming force of the water. Even some 2-3 story concrete buildings remain intact after being literally tipped over on their sides or even turned upside down by the water.

However, the tsunami defenses had been designed for a "maximum credible" tsunami (generally around 7 - 8 m in height: Shuto 2007 - A Century of Countermeasures Against Storm Surges and Tsunamis in Japan; Hayashi & Ishibashi 1998 Design and Construction of Marine Structure in Deep and Rough Seas), despite the existence of historical and geological evidence (discussed in
the body of this work) that some tsunamis reached heights approaching 40 m! The Tohoku tsunami reached at least 38 meters in one place (see the video below "Measuring the tsunami height of 38 meters at Aneyoshi", and 10 to 20 meters in many places (including at the Fukushima Daiichi Nuclear Power Plant). As documented for each Prefecture, the Tohoku tsunami effectively erased many tsunami defenses, villages, towns and small cities as indicated in Figs 1 and 2 at the top of this page. However, as can also be seen in these figures, educational institutions and hospitals were often deliberately placed on the tops of hills as another form of tsunami defense. These survived. Despite the physical damage, many people escaped to high ground due to effective tsunami prediction and warning systems (highly audible in many of the videos) and practice drills. In other cases, as observed in the 3:46 min video above, the existence of tsunami defenses may have increased fatalities by giving residents a false sense of security, leading some to delay their escape until too late (Video 1). Another video discusses the experiences in Tarou/Taro (from NHK World). 

Video 1

Tsunami defenses were not good enough

(left). Shows snippets of the destruction of the city of Kamaishi that was supposedly protected by the world record tsunami wall, and wonders if complacency did not contribute to the number of fatalities.

A variety of media are used to document the extent of tsunami damage along the whole of the east coast of Honshu, the main island of Japan from the northern end of the island to the latitude of Tokyo. This extent includes four nuclear power complexes, including the 6 reactors at Fukushima Daiichi. Experiences at the reactor sites will be documented on another site. The intent of the extensive and highly explicit imagery of the present page is not to provide disaster "porn", but to make an indelible impression on those viewers who may find themselves planning, designing, engineering, managing or operating engineered artifacts used by people that risk analysis and mitigation are not abstract activities. The planet we live on fac
es us with a variety of rare but potentially catastrophic events. Large earthquakes and tsunamis are the most familiar, in that a significant proportion of the world's population may face one or more in their lifetimes. However, there are other rarer, potentially even more destructive events that will certainly happen somewhere in the world over time-scales of a century or so. Some are even potentially civilization ending if not mitigated. These will include
These are all rare events, but it is certain similar events will happen again that planners, managers and e

Measuring the tsunami height of 38 meters at Aneyoshi

ngineers should keep in mind. Real people's lives may depend on how engineering projects are built and operated.

Video 2. Japanese language video discussing & demonstrating how the effects of the tsunami have been measured along the southern coast of Sanriku http://www.youtube.com/watch?v=VvgwzDDxtjo.

Here, the nature and effects of the recent tsunami will be visually demonstrated at a number of sites along the length of Honshu. Media includes a variety of video (e.g., of the Aneyoshi area of Iwate Prefecture to the right) and photographic evidence in the public domain on the Web from the ground, air and space. Most images have been located and controlled against landmarks identified in Google Earth. These locations can be downloaded into your local implementation of the freely available Google Earth by clicking the image below (to implement Earth go to Obtaining and Using Google Earth).

Figure 2. Locations where tsunami effects are documented. Click the graphic to open Google Earth. When this is open you can then zoom in and navigate to particular markers in space. You can also navigate in time by clicking the clock icon just below Earth's menu bar, and then by using the slider to locate historical imagery.

Locations will be explored from north to south along the coast. (Note: if the time slider does not show in the upper left corner of Google Earth when an Earth link is selected, and the the image for the specified date is not displayed, you may have to manually click the clock icon in the row below Earth's menu bar, and wait a few seconds before Earth tracks back to the specific time.)

A series of prefecture specific pages map and link to the array of satellite, live video and photographic evidence regarding the dynamics and immediate effects of the Tohoku tsunami along the Pacific Coast of Honshu and from the northern end of Hokkaido south to Chiba Prefecture opposite Tokyo. Click location maps in the right-hand column to open Google Earth (see Obtaining and Using Google Earth if you do not already have it installed). In Earth you may navigate and zoom (often down to a resolution on the ground of a meter or less). Clicking the clock icon below the menu bar or View/Historical Imagery will toggle navigation through time to display images from before and after the tsunami. Locations of most videos and photographic images are also mapped as accurately as possible relating visual clues in the videos and images to Google's satellite views. Locations of some preliminary tsunami height measurements are indicated with yellow pushpin icons.

Comprehensive aerial multispectral survey data detailing immediate post-tsunami damage is available through the Kokusai Kogyo Group. Many of the links lead to pages in Japanese, but these can readily be converted to intelligible English using Google's translate function
.

Comprehensive records on tsunami heights based on detailed field observations as reported by The 2011 Tohoku Earthquake Tsunami Joint Survey Group are available through the 2011 Off the Pacific Coast of Tohoku Earthquake Tsunami Information web site. The details are in Japanese, but can be readily converted to understandable English
using Google's automatic translate function. To turn this on, find [Translate] on the menu bar at the top of the browser window (or find it by clicking the [More] pulldown menu) and click [Translate]. This gives you the opportunity to select From: (e.g., Japanese) and To: (e.g., English) languages. When a Japanese language web page is encountered in the browser, it should then be translated automatically. (For details on using Google's Translate and other functions see Translating with Google and Hall et al. (2010) Using Google’s Apps for the Collaborative Construction, Refinement and Formalization of Knowledge.

The Tsunami Damage Mapping Team of the Association of Japanese Geographers have prepared maps showing the areas of inundation for Prefectures from Aomori in the north to Fukushima in the south (see Index to Maps). The map on the right, for Kesennuma is typical. Click the figure for the full resolution map. On all maps, the red line indicates the limit of the areas inundated, and the blue shading heavily damaged (i.e., "wiped out") residential areas. These maps exist for all areas of these prefectures discussed, but will not be specifically cited since the raw evidence is relatively imperative in the Google Earth views.


Fig. 3. Tsunami inundation surrounding Kesennuma Bay.