The Asia-Pacific Journal | Japan Focus Volume 9 | Issue 20 | Number 4 | Article ID 3531 | May 09, 2011

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Danger in the Lowground: Historical Context for the March11, 2011 Tōhoku Earthquake and Tsunami　　低地の危険性−−2011年3月11日東北大地震と津波の歴史的背景 •Japanesetranslation available

Gregory Smits

Danger in the Lowground: HistoricalContext for the March 11, 2011Tōhoku Earthquake and Tsunami[Updated June 13, 2011]

A Japanese translation is available here(https://apjjf.org/data/3531SmitsJapaneseTranslationV2.pdf).

Gregory Smits

The March 11, 2011 Tōhoku Earthquake andthe tsunami it generated was a classic case ofnatural hazards such as severe ground motionand seismic sea waves coming into contact withhuman society to produce a multi-dimensionalnatural disaster. Throughout Japanese history,writers often initially referred to such events as“unprecedented.” As time passed, othercommentators would point out that in fact suchevents were “normal” in that they occurredrepeatedly in the past. Similarly, this paperseeks to provide historical context for therecent disaster in two broad senses. First, Iexamine the earthquake and tsunami as part ofa long, ongoing sequence of geological events.Then I focus on the human reaction toearthquake-tsunami combinations similar tothose of 2011, with particular attention toevents that took place in the modern era.

Tsunamigenic earthquakes originating near theJapan Trench have occurred periodically. Theedge of the Pacific Plate subductuing under aportion of the North American Plate sometimescalled the Okhotsk Plate creates the Japan

Trench. Strong earthquakes originating in thisoffshore region typically generate sequences ofse ismic sea waves ca l led tsunamis .Tsunamigenic earthquakes originating near theJapan Trench usually, but not always, causesevere ground motion, as was the case onMarch 11, 2011. This M9 earthquake is thestrongest known earthquake to have shakenany part of Japan, and tsunami heightsapproached 38 meters in some areas. In theabsence of knowledge of the seismologicalhistory of the Tōhoku region and adjacentoffshore areas, the recent disaster may appearunprecedented. Instead, however, it was arecurrence of past seismic events. Waves ashigh as 38 meters demolished precisely thesame coastal areas in 1896, and waves as highas 28 meters caused vast destruction along theSanriku coast (Pacific coast areas of Aomori,Iwate, and Miyagi prefectures) in 1933.

This paper examines past tsunamigenicearthquakes striking the Sanriku coast ascontext for the March 11, 2011 disaster. Foradded perspective on the importance ofhistorical memory, I discuss a tsunami disasterin Osaka in 1854 in connection with the AnseiNankai Earthquake. A close examination ofreactions to the 1896 Meiji Sanriku Earthquakeand the 1933 (Shōwa) Sanriku Earthquakesuggests that fundamental changes in regionalpatterns of settlement and building wouldmitigate any future disaster. If the past is anyguide to the future, however, it is unlikely thatin the longer term people will avoid dwelling intsunami-prone areas.

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G e o g r a p h i c a l a n d G e o l o g i c a lConsiderations

The Tōhoku region is subject to shaking fromfault ruptures in four types of locations: 1)ocean trench earthquakes off the Sanriku orFukushima coast, 2) intra-plate earthquakesoriginating under northern Honshū or thePacific, 3) shallow-focus inland earthquakes; 4)intra-plate earthquakes originating under theSea of Japan. Three of these four types ofearthquakes often generate tsunamis.1 Alongthe Sanriku coast, the geographical interfacebetween human settlements and the sea hasoften amplified the destructive power oftsunami waves. The coastline is deeplyindented, and many of its bays and inlets areshaped roughly like a bugle whose the bell endopens to the ocean. Fishing villages have beenlocated at the narrow interiors of these bays atthe precise point where tsunami wave heightwould be highest because of a fixed quantity ofwater being forced into an increasingly narrow,shallow area.2

Map 1. The Tōhoku region, nearby tectonic plates,and the locus of the 1896 earthquake and tsunami.

Adapted from Yamashita Fumio, Shashin to e de miruMeiji Sanriku ōtsunami (1995), p. 16.

One important phenomenon that occurs inperhaps 10% of seismic events in the Tōhokuregion is that an earthquake causing only mildground motion produces a large, destructivetsunami. These dangerous events are known as“tsunami earthquakes,” a term coined in 1972by Hiroo Kanamori of the California Institute ofTechnology. The destructive Keichō Tsunami of1611 and the Meiji Sanriku Earthquake andtsunami of 1896 are two examples of the earthshaking so mildly that people did not expect themassive tsunamis that followed. Kanamori hasidentified six causal factors for tsunamiearthquakes. The two especially relevant to theMeiji Sanriku Earthquake are that the faultrupture takes place slowly and that the rupturebreaks and displaces accumulated sediments atthe plate boundary. The presence of thesesediments can function to slow the speed of the

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fault rupture. Moreover, the movement of largequantities of sediments can displace water andcontribute to the size of the tsunami. It ispossible to calculate the magnitude of atsunami using tide gauges to measure the totalwidth and distance between the epicenter ofthe earthquake and points on shore the tsunamireaches. Ordinarily, tsunami magnitudesc lose ly t rack the magni tudes o f theearthquakes that generate them, but a tsunamiearthquake can be defined as an event in whichthe tsunami magnitude is significantly higherthan the earthquake magnitude.3

If the sea floor moves too slowly as a faultruptures, there will be no tsunami. Within therange of speed necessary to generate atsunami, an increase in rupture time willdecrease the magnitude and intensity ofshaking, but it will not decrease the size of thetsunami. As a rough rule, tsunamis tend tooccur from rupture speeds ranging fromseveral tens of seconds to about 100 seconds.In the case of the Meiji Sanriku Earthquake,the best estimate is that a portion of the faultabout 250 kilometers long ruptured over thecourse of about 100 seconds. The resultingseismic land waves would have had such a longperiod that people would barely have felt them.The relatively slow fault rupture pushedunconsolidated sediments upward to produce amassive tsunami. In this case, the earthquakemagnitude was roughly 7.2, but the tsunamimagnitude was 8.6.4

The 2011 Tōhoku Earthquake was not atsunami earthquake. Ground motion wassevere, which ideally should have prompted animmediate flight to high ground for thosecapable of doing so. Initial reports indicatehigh survival rates in localities that heeded thewarning that the shaking provided.5 Themaximum height of the tsunami was roughlythe same in 2011 as i t was in 1896 ,approximately 38 meters at the village of Ryōriin Iwate Prefecture (today, Ōfunato-shi,Sanriku-chō, Ryōri).6

Map 2. Tsumani heights at coastal locations in 1896and local fatalities. Adapted from Yamashita Fumio,Shashin to e de miru Meiji Sanriku ōtsunami (1995),

p. 30.

Overall History

The Sanriku coast and nearby areas in theTōhoku region have a long history of largeearthquakes and tsunamis. At night, on July 13,869 (Jōkan 11, 5m, 26d) an earthquake with anestimated magnitude of 8.3 shook the area, andthe tsunami tore through Taga Castle,drowning approximately 1,000 according toNihon sandai jitsuroku (Veritable records of thethree reigns of Japan). Considering therelatively sparse population at the time, 1,000deaths was a major human disaster. Geologistshave recently discovered a sand layer in theSendai Plain dating to the time of this event.7

In the early afternoon of December 2, 1611(Keichō 16, 10m, 28d) very mild shaking thatmany did not feel was the only harbinger of a

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massive tsunami that struck around 2pm.Precise written records indicate the extent towhich the series of three waves penetratedinland, farther even than occurred as a resultof the Meiji Sanriku Earthquake. The Keichōtsunami death toll approached 3,000 in theSanriku area and over 3,000 in the Nanbu-Tsugaru area. Considering that the populationat the time was ¼ what it was during most ofthe Shōwa era, the human disaster was roughlyon a par with the events of 1896 or 2011. Therewas no loss of life or significant damage fromthe shaking, and this lack of warning surelyadded to the death toll.8 In a study of theKeichō event, Hirakawa Arata of TōhokuUniversity has recently concluded that massivetsunamis have flooded the Sendai Plain everyfew centuries. Moreover, the stops along theT o k u g a w a p e r i o d c o a s t a l h i g h w a ycorresponded to areas just beyond the reach ofthe water from the 1611 tsunami. Hirakawaclaims that in the midst of post-Meij idevelopment modern people in the region havelost their acute sense of tsunami danger.9

One item of lore developed in connection withthe 1611 tsunami sheds light on a broadertrend in Japanese earthquake-related culture.The previous year, there had been reports offishermen catching giant sized ayu (sweetfish)and sardines in the area. In hindsight, thisapparent ecological anomaly seemedsignificant to many local residents as aprecursor to the tsunami.10 Throughout Japan’spremodern and modern history, there has beena tendency to suppose l inks betweenearthquakes and the behavior of fish or othermarine life. An April 1, 1932 Yomiuri shinbunarticle, for example, announced that TōhokuUniversity professor Hatai Shinkishi haddemonstrated that when catfish swim in acertain way, an earthquake occurs within 12hours. The fish in Hatai’s lab had allegedlypredicted almost 100 earthquakes.11 The mediaexcitement over Hatai’s research soon faded.Despite much research attention during thetwentieth century, nobody has developed any

useful way to employ fish or other animals asearthquake predictors. Such interest continuesto this day. Reminiscent of the ayu and sardinesin 1610, a recent newspaper article explainedthat the squid catch was unusually high prior toseveral earthquakes between 1946 and 2011,implying some kind of link.12

Reports of unusually bountiful fish catchesappeared in connection with an earthquake andtsunami that struck the Sanriku coast late inthe morning of February 17, 1793. Theearthquake damage was moderate, and onlytwelve people died in the shaking, but manymore died in the tsunami that struck around10am. Because the 1611 disaster and the onein 1793 had occurred in the winter, a local folktheory developed such that tsunamis only strikewhen leaves are not on the trees. This notionwas part of popular lore in August 23, 1856,when a strong offshore earthquake shook theSanriku area. Because the trees were full ofleaves, some people delayed making their wayto high ground and were caught by the fourtsunami waves that soon came sweepingthrough coastal areas.13 In this case, historicalmemory contributed to an inaccurate andpotentially deadly folk theory. More generally,it has long been customary in Japan to assumelinks between atmospheric phenomena andearthquakes or tsunamis, and seismologistssearched for such links well into the twentiethcentury. The gradual acceptance of platetectonics by Japan’s scientific communityduring the 1970s put an end to lingeringseismological interest in the role ofatmospheric phenomena and earthquakes.

The June 15, 1896 Meiji Sanriku Earthquakeoccurred at 7:32pm on the fifth day of the fifthmonth in the old lunar calendar. Villages in thearea had been celebrating the Boys’ Festival,and military organizations were celebratingJapan’s recent victory over China. Gentleground motion and the absence of seawallsexacerbated the disaster. The tsunami struckabout 35 minutes after the earthquake. Three

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main waves of the tsunami swept over thelandscape, and many villages lost the majorityof their inhabitants. The total death toll was21,959, over 10,000 structures were washedaway, and over 7,000 boats and ships weredestroyed or damaged.14

At 2:31 in the morning of March 2, 1933, themagnitude 8.1 Sanriku Earthquake (sometimescalled the Shōwa Sanriku Earthquake) shookresidents awake. Originating near the locationof the 1896 event, the 1933 earthquake was theresult of the rupture of an intra-plate fault.Although geologically different from its 1896predecessor, the 1933 earthquake wasfunctionally similar in that it threw off a largetsunami. The maximum wave height at RyōriBay was 28.7 meters. The Sanriku Earthquakeand tsunami resulted in slightly more than3,000 deaths and over 1000 injuries. Theshaking, waves, and fire combined destroyedover 6,000 houses, and local residents endured77 aftershocks of M6 or higher for six monthsfollowing the main shock.15

It should be clear from this overview that largetsunamigenic earthquakes have occurredrepeatedly in precisely the areas devastated bythe March 11, 2011 event. Writ ing inapproximately 2006, Okada Yoshimitsu pointedout that:

In the Tōhoku region, there is astronger tendency for largeearthquakes and the tsunamis thataccompany them to occur offshore,owing to plate subduction. In theyears to come , there i s anextremely high likelihood of a largeearthquake originating beneaththe sea floor along the JapanTrench.16

Moreover, hazard maps in the front matter ofOkada’s book list the area offshore from Sendaias having a 99% chance of experiencing a

magnitude 7.5 or greater earthquake duringthe next 30 years. The earthquake and tsunamiof March 11, 2011 was the event which Okadaanticipated, reflecting a broad consensus of theseismological community. In this sense, theearthquake was an expected event, at leastamong a small group of experts.

I should emphasize that current knowledge andtechnology is unable to predict earthquakeswith any degree of precision that would be ofpractical use in, for example, allowing fororderly evacuations of dangerous areas. To saythat the recent earthquake was an expectedevent means that knowledge of the relevantgeological mechanisms and historicalexperience indicated that moderately largetsunamis are likely to occur in the area everyfew decades, and extremely large anddestructive events are likely to occur every fewcenturies. With this knowledge in mind, itwould probably be prudent to build critical, andpotentially dangerous, infrastructure such asnuclear power plants in light of worst-casescenarios to withstand M9-class shaking andtsunami heights on a par with those of 1896 or2011, plus an additional safety margin.17 The2011 event did moderately exceed expectationsin terms of the sheer quantity of energyreleased by the earthquake (magnitude), butthe 1896 event still holds the record fortsunami height, if only by an insignificant fewcentimeters. Had people heeded the warningson still-extant stone monuments from 1896 notto build below the point of the monument, theirhouses would have been safe from the recenttsunami.18

Update: According to a news report on June 12,2011, the March 11 tsunami reached amaximum height of 40.5 meters, thusexceeding 1896 levels. It is therefore possiblethat some locations that would have been safein 1896 would not have been safe in 2011.

The Case of Osaka

Before taking a closer look at the Tōhoku

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situation, the case of Osaka provides usefulcomparison. Two massive tsunamigenicearthquakes shook Osaka and large areas alongthe coast in 1707 and 1854. Until March 11,2011, many historical seismologists regardedthe 1707 Hōei Earthquake as the most powerfulknown earthquake to have shaken Japan. Itgenerated tsunami waves that washed throughthe coast of Honshū from Suruga Baysouthward, through much of Shikoku, and partsof northern Kyūshū. Like Hōei, the December24, 1854 Ansei Nankai Earthquake (M8.4 ) wasan offshore subduction zone earthquake thatgenerated a destructive tsunami. Both the Hōeiand Ansei Nankai earthquakes weregeologically similar to the 2011 TōhokuEarthquake.

The Hōei Earthquake and tsunami causedcoastal villages to develop evacuation plansthat usually involved the entire communityassembling at a temple, shrine, or othersuitable location on high ground. Anticipatingthe need occasionally to spend a night or two atsuch locations, some villages constructedsimple shelters at the evacuation area.Throughout the area within range of the 1707tsunami, generations of rural coastal residentsfled to high ground when the earth shook.Sometimes the move proved unnecessary, butthe Hōei devastation loomed large in historicalmemory. A writer living in the Kii Peninsula, forexample, explained that “fearing a tsunami,people set up lean-to shelters in themountains,” and letters, diary entries, andother documents dealing with rural areasregularly describe lowland villages in termssuch as “Owing to tsunamis, everyone had setup huts in the mountains, and not a singleperson was dwelling” in the lowland village.19

Not all accounts, however speak of an effectiveresponse. “There is a saying that complacencyis the greatest enemy (yudan-taiteki),” began ashort essay that went on to criticize people ofthe present for ignoring the lessons of the 1707Hōei Earthquake and tsunami “as if it were anancient tale” and not currently relevant

knowledge.20 The writer was referring toOsaka.

Although the Hōei tsunami damaged Osaka,between 1707 and 1854, there had been asubstantial turnover in the city’s population,including an influx of people from inland areas.Historical memory of the type needed topreserve effective tsunami evacuation practiceswas weak or absent. As early as the 1662Kanbun Earthquake, many residents of Osakafled to boats moored in the city’s rivers andremained there for several days or even weeksto escape the nerve-wracking shaking fromaftershocks that usually followed majorearthquakes. An order by Osaka’s Machibugyōin 1854 prohibiting onboard drinking partiesclearly indicates that the city authoritiesregarded fleeing to boats as a perfectly viableoption, provided people remain sober.21 Inlandearthquakes such as Kanbun were morecommon than offshore tsunamigenic events,and by 1854, the Hōei Earthquake wouldindeed have seemed like “an ancient tale” tothe few people in Osaka who even knew aboutit. Much more relevant would have been themagnitude 7.25 Iga-Ueno Earthquake of July 9,1854, approximately six months prior to AnseiNankai. As many people as possible rode outthe many Iga-Ueno aftershocks in the relativecomfort of boats in the rivers. Moreover, theAnsei Tōkai earthquake of the December 23caused some shaking in Osaka but no tsunami.The result of the mass flight to boats on the 24th

was tragic and dramatic. The massive tsunamiwaves that swept up the rivers crushed nearlyall of the boats, resulting in perhaps 800deaths.22

The case of Osaka in 1854 serves as a preview.Some of the basic conditions of modern lifesuch as the relatively easy movement of peopleand a weakening of traditions in localcommunities contributed to the fatal lack ofhistorical memory. Similar forces have been atwork in the Tōhoku region and elsewhere sincethe 1890s.

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A Closer Look at 1896 and 1933

Returning to the Tōhoku region, I examine thetsunamis of 1896 and 1933 in detai l ,particularly the short term and longer-termresponses to these events. The scope of thedisaster in 1896 was overwhelming at first.Without warning, mud and sand buried about70 coastal communities, bodies mixing in withdebris from smashed houses. In IwatePrefecture, where about 20,000 died, 125women died for every 100 men. The mainreason was that men often set out in theevening for night fishing. In one village, forexample, about 40 fishermen in five or six boatswent out the evening of the tsunami. At sea,they experienced nothing unusual and wereshocked to see their demolished village as theyapproached shore. Many such returningfishermen heard voices calling out for help inthe dark as they returned. Local lore regardedvoices in the water as those of ghosts.Moreover, answering the calls of such ghostswould result in their pulling the responder intothe water. This situation resulted in delays inthe fishing boats mounting rescue operations.23

Figure 1. Bodies line the ground outside a localtemple in Kama’ishi, 1896. From YamashitaFumio, Shashin to e de miru Meiji Sanriku

ōtsunami (1995), p. 20

In the hardest hit villages, the tsunami killed

the majority of residents. Tarō Village, forexample, lost 83% of its residents. Only 36 ofits population of 2,000 survived. The waveswashed away all public infrastructure plus 285of 336 houses, and because the village facedthe Pacific Ocean directly, the water sweptmost bodies out to sea. In the days followingthe tsunami, a large number of these bodieswashed up on shore.24 Owing to warm summerconditions, a lack of people, and a lack ofinfrastructure, disposal and identification of themany bodies was a major problem. Sometimesdebris became a funeral pyre for unclaimedbodies. Hirota Village used fishing nets torecover bodies at sea. As many as 50 came upin one sweep, so many that only half could bebrought to shore at a time.

Figure 2. Drawing of the recovery of bodies at Hirota,1896. From Yamashita Fumio, Shashin to e de miru

Meiji Sanriku ōtsunami (1995), p. 21

Bodies in the ocean soon became encrustedwith sea creatures, and starving dogs set uponcorpses on land, sometimes biting people whotried to restrain them. Bodies from one villageoften f loated to other areas, furthercomplicating identif ication. In IwatePrefecture, 10,200 of the 18,158 bodiesrecovered were d isposed of in massgraves.25 This gruesome aftermath would havemade a strong impression on survivors and

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people entering the area.

The total monetary cost of the 1896 disasterwas between 7,100,000 and 8,700,000 yen,approximately 10% of the national budget forthat year. The total cost of the 1995 KobeEarthquake was also just over 10% of thenational budget, so the financial impact of bothevents was roughly comparable.26

Hattori Kazumi, governor of Iwate Prefecture,issued general instructions published on June20 in the local newspaper, the Iwate kōhō:

The present tsunami that struck 60ri off the Tōhoku coast is anunprecedented (zendai-mimon)catastrophe, and it is essential tobe alert to maintain hygiene in theaffected areas to the best of ourability. Especially after a disaster,fearsome outbreaks of epidemicand contagious disease occur. . . .It is especially necessary for us toattend to steps such as setting upevacuation centers, treating thewounded and sick, properlydisposing of corpses, potablewater, and cleaning up the debriswidely strewn about the disasterarea.27

This concern with “hygiene” (eisei) appearsfrequently in documents related to thisearthquake, and it was typical of thetimes.28 Governor Hattori’s general directivebecame a detailed set of instructions forcleansing, burning, disinfecting, and takingother measures thought to prevent the spreadof disease. For example, “Periodically open thewindows and light a fire to maintain dryness inhouses. In particular, this should be donebefore sleeping.”29

Other steps in dealing with the immediateaftermath of the tsunami included dispatching

medical personnel and gangs of laborers to thearea, measures to control theft and looting(sometimes at the hands of the gangs oflaborers), and attempts to control hoarding andprice gouging. In one case, the policeinvestigated a rice dealer in Miyako-chōclaiming his shelves were empty and found thathe had enough rice in stock for 20 days. Theylectured him on the evils of price gougingduring this unprecedented (mizō) emergencyand forced him to sell his stock at a moderateprice.30 Although the details were different in1896, the general problem of hoardingnecessities appeared in 2011, even in areas notdirectly affected by the disaster.

The central government dispatched specialiststo the disaster area, and interior ministerItagaki Taisuke left Tokyo for a tour of theregion on June 22nd. Each of the affectedprefectures established relief centers. MiyagiPrefecture, for example, created the TemporaryTsunami Bureau (Kaishō rinjibu). It operatedfor 67 days from June 20 to August 25. Peoplefrom Iwate, Miyagi, and Aomori prefecturesliving in Tokyo established an agency tocoordinate the solicitation, collection andshipping of aid to the afflicted regions.31

Figure 3. The seawall at Tarō, sometimes called “TheGreat Wall” by local residents. From Yamashita

Fumio, Shashin to e de miru Meiji Sanrikuōtsunami (1995), p. 41.

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Of particular interest is the longer-termrecovery and rebuilding effort. Let us firstconsider the specific case of Tarō, the villagethat lost 83% of its population. Following the1896 disaster, the remnants of Tarō and somenewcomers attempted to move to a saferlocation at the base of a mountain butultimately failed to do so. The 1933 tsunamionce again wiped out most of the village.Instead of relocating, the remnants of Tarōbegan constructing a 10-meter high seawall,the full length of which was completed soonafter the war. Postwar Tarō Town thrived in theshadow of this fortress-like seawall, and notalways behind it.

On a recent visit to Tarō, Itō Kazuaki wassurprised to see houses and shops on theseaward side of the wall.32 A recent internetsearch using the term “田老町” (Tarō-chō)reveals photos of the seawall and surroundingareas, memorials to the 1896 and 1933disasters, a tsunami evacuation direction sign,and sadly, the twisted wreckage of the townafter March 11, 2011.33

The destruction of the “Model City” of Tarō

In 2003, on the 70th anniversary of the 1933disaster , the town formal ly issued a“Declaration of a tsunami defense town”(Tsunami bōsai no machi sengen) in honor ofthose who died and styled itself as a “Disasterdefense town” (Bōsai no machi, also the title ofa booklet published by the local board ofeducation).34

Figure 4. Tarō in the wake of the March 11, 2011disaster. The great seawall was not tall enough to

hold back the tsunami. Source(http://kenplatz.nikkeibp.co.jp/article/const/news/20110406/546846/?SS=imgview&FD=1153259116) (acce

ssed 5-13-2011)

Tarō boldly standing up to the fury of the seai s , o f course , a t rag ic tes tament tooverconfidence. It is hardly unique in thisregard. In examining all of the communitiesthat made plans to relocate after the 1896disaster, a majority were either unable to puttheir plan into action or gradually moved backto low-lying areas. Communities that relocatedto higher ground and remained there usuallysuffered little or no damage in 1933. Somespecific examples illustrate the range ofpossibilities. Funakoshi in Iwate relocated tohigher ground by extending a road up amountain and building houses on either side ofit. Tanohama, which had been wiped out,planned to merge with Funakoshi and re-distributed land at the same location. NewTanohama residents, however, unaware of thedanger, gradually relocated closer to the coast.In 1933, Tanohama was destroyed again, butFunakoshi escaped with no damage. Yoshihamaescaped damage in 1933 by similarly extendinga lowland road up a mountain and relocatingthere. Ryōri moved several residences to highground, but over the years, they returned tothe original location. The vil lage was

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devastated again in 1933. Hashikami in Miyagientirely relocated to high ground, assisted bythe prefecture building a new road. Damage in1933 was light.35 Notice the key role ofinfrastructure in the form of roads to supportcommunities that successfully relocated.

It is significant that the trend to return tooriginal locations, or otherwise to abandon safevenues and move lower and closer to the coast,greatly accelerated after the passing of 10years. It is as if historical memory, or at leastthe sense of danger, greatly diminished afterthe passing of a tsunami-free decade. Otherreasons for remaining in or returning to low-lying areas included convenience for those inthe fishing industry, a lack of potable waterafter moving, inconvenient road networks, themain part of the community remaining where ithad been, attachment to ancestral land, atendency gradually to make temporary hutsused for work into permanent dwellings, and aninflux of people into the area withoutknowledge or experience of tsunamis.36 Manysimilar issues are likely to play a role in thefuture of the region.

Looking Ahead

“Tsunami tendenko” is a well-known expressionin the Tōhoku region. It means that when atsunami is on the way, run for dear life and payno attention to anything or anyone else. Theexpression highlights the sense of urgency thatbecame so clear to people around the worldwatching videos of the sea’s deadly advance onMarch 11, 2011. Although a variety of lessonsare prominent now, in the immediate aftermathof the disaster, this study suggests thathistorical memory and an acute sense ofdanger will fade fairly rapidly. Individuals andsociety as a whole obviously face a majorchallenge moving forward in the region,particularly with respect to rebuilding.Demographics may be a factor in favor oflonger-term safety. With the population of thearea already declining, rebuilding in safer

locations may be slightly more practical than ageneration ago. Yet this may be weighedagainst factors that make the original locationdesirable.

The recent disaster revealed both strong andweak points in Japan’s earthquake and tsunamipreparedness. Earthquake-resistant buildingsin the Tokyo area generally performed asexpected, as did other systems such asemergency shut-down mechanisms in trains.The shortage of food and fuel in Tokyo, despitereceiving only a glancing blow, suggest muchgreater distribution problems in store should alarge urban area be hi t with a majorearthquake. The issue of nuclear power plantsafety, of course, is a relatively new and vexingproblem in a country with few energy options.

Ideally, the recent Tōhoku disaster should workagainst complacency in other areas of Japanvulnerable to large earthquake and tsunamicombinations. The Tokyo areas is vulnerableboth to an ocean trench earthquake like theGreat Kantō Earthquake of 1923 and to therupture of faults under the city itself such asoccurred in the Ansei Edo Earthquake of 1855(no tsunami). Strain has been accumulatingbehind the Nankai Trench such that areas fromthe Kii Peninsula to northern Kyūshū could atany time suffer a Tōkai or Nankai earthquake(or both, as in 1707 and 1854), which wouldalmost certainly generate massive tsunamis. Allof these possibilities involve major urban areas.

Finally, the 2011 Tōhoku Earthquake is directlyrelevant to the Pacific northwest coast of theUnited States and southern Canada. In thisregion precisely the same type of M9-classseismic events have happened approximatelyevery 500 years for the same reason,subduction of the Pacific Plate. The most recentsuch event took place on January 26, 1700.Estimates of the earthquake’s magnitude rangefrom 8.7-9.2. Extensive Japanese records of an“orphan tsunami” (minashigo Genroku tsunami)led investigators to discover that an earthquake

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and tsunami had devastated coastal areas ofthe Pacific Northwest, even submerging entireforests. Tsunami evacuation signs are nowcommon in coastal areas of Oregon andWashington State, and researchers havediscovered extensive evidence in the myths andlegends of native peoples of massiveearthquakes and tsunamis in the past.37 Outsideof Native American lore, however, today’sPacific Northwest possesses no collectivememory of disastrous seismic events and is inmany other ways less prepared for thepossibility of a disaster than its cross-plateneighbors in the Tōhoku region of Japan.

Gregory Smits is an Associate Professor ofHistory at Pennsylvania State University. He isa social and cultural historian of Japan, whoseinterests range from the fifteenth through theearly twentieth centuries. A specialist in thehistory of the Ryukyu Kingdom, he is the authorof Visions of Ryukyu: Identity and Ideology inEar ly -Modern Thought and Po l i t ics(http://www.amazon.com/dp/0824820371/?tag=theasipacjo0b-20) and co-editor with BettinaGramlich-Oka of Economic Thought in Early-M o d e r n J a p a n(http://www.brill.nl/economic-thought-early-modern-japan). He has recently completed a book-length study of earthquake culture in early-modern Japan”

Recommended citation: Gregory Smits, Dangerin the Lowground: Historical Context for theMarch 11, 2011 Tōhoku Earthquake andTsunami, The Asia-Pacific Journal Vol 9, Issue20 No 4, May 16, 2011.

Notes

1 Okada Yoshimitsu, Saishin Nihon no jishinchizu (Tōkyō shoseki, 2006), p. 52.

2 Itō Kazuaki, Jishin to funka no Nihonshi(Iwanami shoten, 2002), pp. 106-7.

3 Koshimura Shun’ichi and Shutō Nobuo, “MeijiSanriku jishin tsunami,” in Chūō bōsai kaigi,1896 Meiji Sanriku jishin tsunami hōkokusho,2005, pp. 15-17.

4 Koshimura and Shutō, “Meiji Sanriku jishintsunami,” pp. 15, 17-20. See diagram 2-9 forthree possible models for this process. Mostreference books do not distinguish betweenmagnitudes for the earthquake versus thetsunami and typically state a magnitude of 8.5for the entire event.

5 See, for example, Jay Alabaster, “Tsunami-hittowns forgot warnings from ancestors.”Associated Press, April 6, 2011. Alabastermentions the “tightly knit community ofAneyoshi,” part of Miyako City, as a place thatfared relative well in the recent disaster.

6 For details of the complexities of tsunamiheight calculations and the conclusion that a 38meter height at Ryōri is a reasonable estimate,see Koshimura and Shutō, “Meiji Sanriku jishintsunami,” pp. 25-30.

7 Shinsai yobō chōsakai, eds., Dai-Nihon jishinshiryō, vol 1 (kō), pp. 38-39, Itō, Jihin to funka,p. 107, and Koshimura Shun’ichi, “Sanrikuchihō no tsunami saigai gaiyō,” in Chūō bōsaikaigi, 1896 Meiji Sanriku jishin tsunamihōkokusho, 2005, p. 3.

8 Koshimura, “Sanriku chihō,” pp. 3-4, and Itō,Jishin to funka, 107. For an example of adetailed account of the event describing theprecise reach of the water, see Tōkyō daigakujishin kenkyūjo, ed., Shinshū Nihon jishinshiryō, ho (supplement), p. 98.

9 “Higashi Nihon daishinsai: senjin wa shitteita‘rekishi gaidō’ shinsui sezu,” in Mainichis h i n b u n , A p r i l 1 9 , 2 0 1 1 , l i n k(http://mainichi.jp/select/wadai/news/20110419k0000e040095000c.html).

10 Koshimura, “Sanriku chihō,” p. 4.

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11 “Namazu ga ugoku to kanarazu jishin gaokoru,” in Yomiuri shinbun, April 1, 1932,morning edition, p. 7. See also excerpts of apresentation Hatai gave on his research,“Namazu no ugoki de jishin o yochi,” in Yomiurishinbun, October 14, 1932, morning edition, p.4.

12 “Ika toresugi wa dai-jishin no zenchō? . . .senmonka mo kyōmi,” in Yomiuri Online, May1 , 2 0 1 1 , l i n k(http://www.yomiuri.co.jp/national/news/20110501-OYT1T00194.htm?from=yoltop).

13 Koshimura, “Sanriku chihō,” p. 5.

14 Itō, Jishin to funka no Nihonshi, pp. 107-113,and Okada, Jishin chizu, p. 58.

15 Okada, Jishin chizu, p. 59, and Itō, Jishin tofunka no Nihonshi, p. 117. For photos of RyōriBay before and after the 1933 tsunami, see thiss i t e(http://protea.dbms.cs.gunma-u.ac.jp/TSUNAMI/tsunami_data/IwateShowaShinsai_kawamoto/image/IwateShowaShinsai_00024.jpg).

16 Okada Jishin chizu, p 50.

17 As Rodney C. Ewing and Jeroen Ritsemapoint out, “In the case of the Fukushima Daiichipower station, the magnitude of the earthquake(9.0 on the Richter scale, or M9) andsubsequent tsunami (with a reported waveheight of 14 meters) exceeded the credibleevent on which the nuclear power plant'sdesign was based.” See “Underestimatingnuclear accident risks: Why are rare events socommon?” Bulletin of the Atomic Scientists,M a y 3 , 2 0 1 1 , l i n k(http://www.thebulletin.org/web-edition/roundtables/fukushima-what-dont-we-know#rt8750).

18 Regarding these stone monuments, see thewidely reproduced article by Martin Fackler(http://www.nytimes.com/2011/04/21/world/asia/21stones.html), “Tsunami Warnings for theAges, Carved in Stone,” New York Times, April

20, 2011, A6.

19 “Zoku jishin zassan,” in Shinsai yobōchōsakai, Dai-Nihon jishin shiryō, pp. 420, 423.For more examples of villagers fleeing to highground in advance of tsunamis, see, pp. 419,462, 467, 469-471, 482-483.

20 “Jishin nikki,” in Shinsai yobō chōsakai, Dai-Nihon jishin shiryō, vol. 2 (otsu), p. 488.

21 Nishiyama Shōjin, “Ansei nankai jishin niokeru Ōsaka de no shinsai taiō,” in Chūō bōsaikaigi, 1854 Ansei tōkai jishin, Ansei nankaijishin hōkokusho, p. 51. The decree was issuedone day after the main shock of the Tōkaiearthquake, just before the Nankai earthquakeand its tsunami struck.

22 Nishiyama, “Ōsaka de no shinsai taiō,” pp.51, 55-59, 62. For an image of the carnage,from the popular press, see this address(http://gazo.dl.itc.u-tokyo.ac.jp/ishimoto/1/01-035/00001.jpg)(upper left image).

23 Shutō Nobuo and Koshimura Shun’ichi,“Meiji Sanriku jishin tsunami ni yoru higai,” inChūō bōsai kaigi, 1896 Meiji Sanriku jishintsunami hōkokusho, 2005, pp. 22-25.

24 Itō, Jishin to funka, p. 113 and Kudō andKoshimura, "Higai," p. 38.

25 Shutō and Koshimura “Higai,” pp. 38-41.

26 Shutō and Koshimura, “Higai,” pp. 45-46.

27 For a thorough discussion of the emergingconcept of hygiene, including in Meiji Japan,see Ruth Rogaski, Hygienic Modernity:Meanings of Health and Disease in Treaty-PortChina (Berkeley: University of California Press,2004).

28 Quoted in Shutō Nobuo and KoshimuraShun’ichi, “Gyōsei no ōkyū taiō,” in Chūō bōsaikaigi, 1896 Meiji Sanriku jishin tsunamihōkokusho, 2005, p. 47.

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29 Shutō and Koshimura, “Gyōsei,” p. 48.

30 Shutō and Koshimura, “Gyōsei,” pp. 49-50.

31 Shutō and Koshimura, “Gyōsei,” pp. 51-59.

32 Itō, Jishin to funka, p. 118 and Shutō Nobuoand Koshimura Shun’ichi, “Meiji sanrikutsunami saigai kara no fukkō,” in Chūō bōsaikaigi, 1896 Meiji Sanriku jishin tsunamihōkokusho, 2005, p. 91.

33 See also “Bōsai no machi mo kaimetsu . . .T a r ō n o h i g e k i . ” L i n k(http://matome.naver.jp/odai/2130072798254688201).

34 For the text of the declaration, photos, anddetails of the 1933 disaster and subsequentseawall, see Yamashita Fumio, “Sanriku KaiganTarō-chō ni okeru ‘tsunami bōsai no machisengen’ to dai-bōchōtei no ryakushi,” in Rekishijishin, no. 19 (2003), pp. 165-171, link(http://sakuya.ed.shizuoka.ac.jp/rzisin/kaishi_19

/25-Yamashita.pdf).

35 Shutō and Koshimura, “Fukkō,” pp. 91-92.

36 Shutō and Koshimura, “Fukkō,” pp. 92-93.

37 For a detailed analysis of the orphan tsunamisee Brian F. Atwater, et al., The OrphanTsunami of 1700 (Minashigo Genroku tsunami):Japanese clues to a parent earthquake in NorthAmerica (Oya-jishin wa Hokubei seikaigan niita) (Reston, VA: United States GeologicalSurvey, distr ibuted by University ofWashington Press, 2005). This book is alsoavailable in digital form to the public here(http://pubs.usgs.gov/pp/pp1707/). Regardingmyths and legends as clues to past seismicevents, see R.S. Ludwin and G. J. Smits,“Folklore and earthquakes: Native Americanoral traditions from Cascadia compared withwritten traditions from Japan,” in L. Piccardiand W. B. Masse, eds. Myth and Geology(London: The Geological Society, 2007), 67-78,86-91.

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