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Hokkaido Nansei-Oki Tsunami, July 12, 1993 |
| On July 12, 1993, a magnitude 7.8 earthquake occurred off the west coast of Hokkaido and the small offshore island of Okushiri in the Sea of Japan. In two to five minutes the tsunami, one of the largest in Japan's history, engulfed the coastline of Okushiri Island and the central west coast of Hokkaido. Almost two hundred fatalities were associated with the event, with more than half attributed to the tsunami. The $600 million in property losses were attributed primarily to the tsunami. This tsunami caused spectacular localized damage, especially on the southwestern shores of Hokkaido and on Okushiri Island. This slide set shows damage to ships, dwellings, and businesses, and unique views of clocks stopped in time by the tsunami. |
Tsunami and fire damage SE Okushiri Is. | |
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A view of tsunami and related fire damage on southeast Okushiri Island in the community of Aonae. Photo orientation is looking northeast. Numerous fires broke out following the tsunami, adding to the property loss and misery. More than 120 people were killed in Japan (Okushiri and Hokkaido Islands) by the tsunami. Photos provided by: Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Tsunami damage at Aonae, Okushiri Is. | |
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Aonae, Okushiri Island, looking southeast. Structures in the foreground were damaged by fires fueled by above-ground kerosene and propane tanks following the tsunami. The concrete steps provided a means of escape for some residents following the strong earthquake. The steps were originally installed for residents to easily walk between the housing area on the bluff (not visible) and the community area near the sea. Many residents remembered the May, 1983, earthquake and tsunami and used this previous experience to escape the deadly tsunami waves in 1993, using the steps as the fastest way to safety. Without this previous knowledge, the casualty count would probably have been much higher. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Clock at Aonae showing arrival time of wave | |
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Numerous battery-operated clocks were found scattered in the debris. These provide a rough estimate of the arrival time of inundating, destructive waves. The salt water shorted the electrical mechanism in the clock, causing it to stop. This clock at Aonae, Okushiri Island, shows a travel time (not necessarily for the first wave, but the first inundating wave at this specific location in Aonae) of some fifteen minutes following the earthquake. Clocks on the west side of Okushiri Island showed travel times of as little as six to seven minutes. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Scattered debris at Aonae, Okushiri Is. | |
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Debris scattered by the tsunami at Aonae, Okushiri Island. Most of the homes on Okushiri are framed in wood and the debris trail largely consisted of wood, roofing materials, and personal effects scattered randomly about the inundation area. The clock in the foreground shows a damaging tsunami wave travel time of eight minutes. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Beached fishing boat at Aonae, Okushiri Is. | |
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Aonae, Okushiri Island. Fishing boat (configured for catching squid) is beached high and dry near a damaged fire truck. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
View to north of damage to prosperous tourist area at Aonae, Okushiri Is. | |
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Aonae, Okushiri Island, looking north. Note that the red/white lighthouse is leaning to the northeast. Damage to the lighthouse was caused by the earthquake and not the tsunami. Debris in the foreground is all that remains of a prosperous tourist area occupied by small shops, houses, and kiosks. Concrete foundations and pads, wiped clear of houses and other structures, can be seen in the debris. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
View to south of above area | |
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Aonae, Okushiri Island,looking south. An obelisk in the distance survived the damaging tsunami waves that rose to a height of 5-10 m at Aonae. Note how the waves undercut the concrete pad in the foreground. No wood-framed structure survived the tsunami waves in this immediate area. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Debris scattered near harbor at Aonae, Okushiri Is. | |
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Note the plastic containers and other debris scattered near the harbor at Aonae. Many of the personal and business effects show that Aonae was a prosperous tourist community with a well established squid and sea urchin fishery. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Small fishing boats deposited near harbor at Aonae | |
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Numerous small and large fishing boats were scattered by the tsunami waves and deposited in a variety of places. Near the harbor at Aonae, these boats were forcefully thrust into a seafood processing plant. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Clock half burried in sand shows travel time of twenty minutes | |
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Revealing a tsunami wave
travel time of twenty minutes, this clock was found half buried in sand with other debris deposited by the tsunami at Aonae. Note that the small
reinforced concrete building in the background survived the damaging
tsunami waves. |
Large barge that was moved 75 m by waves | |
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A large 70-m long barge was moved 75 m from the harbor by the flooding tsunami waves. The crane on the barge is used to lift concrete units from the nearby fabricating area to breakwaters and protective bulkheads surrounding the harbor area. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Fishing boat deposited on concrete shore protection barrier, Aonae | |
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A fishing boat was deposited on top of a concrete shore protection barrier at Aonae. Note wood debris from houses and other structures scattered about the area. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
A small valley on the west side of Okushiri Is. | |
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On the west side of Okushiri Island many locations experienced a maximum runup exceeding 20 m. This small valley leading to the ocean experienced a spectacular runup of 31 m. Note the debris in the foreground, including a broken steel reinforced concrete utility pole. Discolored and dead plants and grasses are evident on the hillside. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Damage at Monai, west Okushiri Is. | |
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The village of Monai, west Okushiri Island. Except for a few houses on the bluff (not visible) the community was completely destroyed by the tsunami waves. The waves reached an elevation of nearly 20 m above sea level, flooding 300 m inland. Ten persons were killed and 12 houses were destroyed. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Debris Line at Monai, West Okushiri Is. | |
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The village of Monai, west Okushiri Island. The leading edge of the debris line marks the extent of the flooding. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Debris on highway overpass near Monai, Okushiri Is. | |
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Highway overpass near Monai. Note the debris, including a corrugated sheet metal panel, wrapped around the guard rail. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Debris in overhead utility wires on west Okushiri Is. | |
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West coast of Okushiri Island. The tsunami waves deposited debris from the hillside on the overhead utility wires; note the discoloration of plants and grasses. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Vegetation stripped from hillside, west Okushiri Is. | |
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West coast of Okushiri Island. The tsunami stripped plants and grasses from the hillside leaving debris in the overhead utility wires. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |
Waves overtopped roadway, west Okushiri Is. | |
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West coast of Okushiri Island. The Sea of Japan, to the right, in this area has a tide range of less than 0.5 m. Note how the tsunami waves crossed the roadway, splashed onto the hillside and killed/discolored the native plants and grasses. The tsunami reached a height of about 10 meters above sea level. Photos provided by Commander Dennis J. Sigrist, acting Director of the Internaitonal Tsunami Information Center |