Kobe Earthquake – Japan – January 17, 1995

Like the Northridge earthquake that also occurred in a densely populated area, Kobe suffered very extensive damage and many casualties.

Early in the morning of January 17, 1995, Kobe, Japan, experienced the nation’s most destructive earthquake since 1946. Its epicenter was at Awaji, offshore from Kobe, and ten miles below the surface. Damage was extensive and there were many casualties. Over 5,400 were killed, another 26,800 injured, and over 300,000 made homeless. Additionally, around 105,000 buildings were damaged beyond repair and numerous others suffered lesser forms of damage. The financial costs of the earthquake were in excess of 150 billion U.S. dollars.

The Kobe area is dominated by the Philippine Tectonic Plate’s sub ducting action as it moves beneath the Eurasian Plate at a rate of about two inches a year. Great subduction earthquakes arise from this action at average recurrence rates of one hundred years. This part of Japan has the densest number of faults of anywhere in the country and they, like the main sub ducting action, also on average have an annual slippage rate, one much smaller than that of the main tectonic plate. As a result of these lesser fault movements, the Kyoto-Osaka corridor has experienced more intraplate earthquakes throughout history than any other region of Japan.

The quake devastated central Kobe, crushing buildings and homes and filling the narrow streets with debris. Train services, so vital to Japan’s transportation system, came to a sudden stop and all electricity and water provisions were cut off. So complete was the destruction of everything that the term “Great Hanshin Disaster” was born to indicate an event similar to the “Great Kanto Disaster” of 1923. The word “Hanshin” is another term for the Kobe Region. With the loss of all water supplies it became impossible to cope with all the fires that broke out as electrical sparks and flammable materials were thrown together. Thus a firestorm, like the one that engulfed San Francisco in 1906 for the same reason, and lack of water supplies, swept across Kobe. By late on January 17, there were 234 fires and, before the middle of the next day, five hundred conflagrations were consuming the large amounts of flammable materials that lay around.

The destruction that took place along Kobe’s waterfront was another mirror image of the 1906 earthquake, that of liquefaction. All along the waterfront zone of Kobe extensive reclamation work had gone on for decades to provide space for shipping activities and warehouses. The widespread liquefaction that took place destroyed the roads leading to the waterfront installations, collapsed both housing and warehouses, and lowered the ground level across the whole area by several feet. A few buildings that had been erected on deeper geological formations remained intact. Liquefaction extended downward in the reclaimed areas as deep as thirty feet in the wake of the thousands of aftershocks that followed the main quake and the wave movements in these deeper zones of liquefaction damaged several areas farther inland.

Minimum amounts of restoration took several months to complete. Gas and electrical supply lines had been so badly disrupted that even Japan’s extremely efficient system of records was incapable of deciding what line belongs where. Officials had to interview individual family survivors, mass media reports, and a variety of telephone and printed records before reconnecting trunk lines. For water lines, the available pressure was initially inadequate for identifying breaks in the system and when officials tried to reach locations to examine conditions directly they were held up by a total absence of roads. Within the downtown part of Kobe all the main streets were impassable. Removing liquefied sand from damaged pipes was yet another hurdle to overcome before the pipes could be reconnected.