Cemeteries Not So Safe During EarthquakesI have never though of a cemetery as being a safe harbor during an earthquake, but apparently some companies in Japan have studied the option. I found it to be pretty interesting. Check it out below:
The Great Hanshin Earthquake of 1995 in Japan prompted a surge in earthquake-resistance work on buildings in an effort to save lives when the next major temblor strikes. But now, moves are afoot to boost the quake-resistance of heavy gravestones.
The Japan Stone Industry Association, a group of about 1,200 domestic companies in the stone industry, is working with researchers from Kyushu University to study measures to make gravestones less likely to topple in quakes.
The research was born from fears that people who have fled to cemeteries designated as emergency evacuation sites following a quake may be hurt by gravestones that are easily rocked by aftershocks.
Tombstones are usually made by simply piling stones on top of one another without taking any special measures to protect them from quakes.
According to the association, about 80 percent to 90 percent of the tens of millions of gravestones said to be standing in Japan are not believed to have any quake resistance. A strong seismic jolt would easily topple such headstones.
The potential danger posed by gravestones in a quake should not be underestimated.
While not a gravestone, a stone lantern in Wajima, Ishikawa Prefecture, fell and hit a woman on her head, killing her, in the March 2007 Noto Peninsula Earthquake – which was recorded at upper 6 on the Japanese intensity scale of 7.
Many gravestones at a display yard in Kashiwazaki were destroyed in the July 2007 Niigata Prefecture Chuetsu Offshore Earthquake, which also hit upper 6 on the Japanese scale.
Following a series of large temblors of around level 6 on the domestic seismic scale across the nation in 2003, the association established an earthquake study group in 2004.
The study group has been surveying gravestones damaged in disaster zones and researching how to construct gravestones that do not easily topple. In 2005, the group borrowed a Tobishima Corp. seismic simulator in Noda, Chiba Prefecture, and used it in an experiment to shake both traditional Japanese-style and the now more fashionable Western-style gravestones.
The group put different types of headstones on the simulator – those with no earthquake-resistance and those with means to resist the effects of a quake, such as adhesives or metal fittings.
It closely monitored how the gravestones shook and toppled at three seismic levels – lower 6, upper 6 and 7.
The unstrengthened Japanese-style gravestones broke up at the lower 6 level, and toppled or spattered stone at upper 6 or stronger.
Unstrengthened Western-style gravestones, which are shorter than the Japanese-style gravestones and regarded as safer, fell to pieces at the upper 6 level and toppled at level 7.
Gravestones that had individual stones stuck together with adhesive did not collapse so easily. The resistance of those reinforced with metal fittings – either with antislip fittings or those that bound stones together – differed depending on the type of fitting used.
The group’s study of disaster zones found that gravestone foundations were weak in banked sections of cemeteries and would topple easily in quakes.
In some instances, gravestones weighing between 100 kilograms and 200 kilograms were flung four or five meters. “Someone could be killed or injured (under these conditions) at any time,” said Yasuo Kawamoto, vice chairman of the association.
Cemeteries sometimes are used as emergency evacuation sites following a quake in urban areas with a high density of office buildings and homes.
In Tokyo, places such as Aoyama Cemetery in Minato Ward and Zoshigaya Cemetery in Toshima Ward are designated by the Tokyo metropolitan government as emergency evacuation sites.
The metropolitan government believes cemeteries do not pose a great risk at present. “People flee to emergency evacuation sites after a fire spreads following an earthquake and wait for it be brought under control,” an official of the government’s disaster preparation section said. “They aren’t places to protect yourself from tremors.”
However, Aiko Furukawa, an assistant professor at Kyushu University’s Faculty of Engineering who is researching quake-proofing in conjunction with the association, pointed out the actual dangers.
“It’s possible that people won’t be able to get to safety after gravestones topple and scatter about,” Furukawa said. “Evacuees also might get injured if aftershocks topple gravestones.”
All that is written on signposts for such cemeteries in Tokyo is “emergency evacuation site.” Observers have warned that people might mistakenly feel these places are safer than their home or office and evacuate to them even if there is no fire.
Furukawa has estimated the relationship between the strength of tremors and the damage inflicted by toppling gravestones at cemeteries used as emergency evacuation sites.
She believes plots of land where much damage likely would occur in a quake should not be designated as emergency evacuation sites.
The association plans to begin a fact-finding survey of cemeteries designated as emergency evacuation sites.
Kawamoto said: “The land at Aoyama Cemetery has extreme undulations and is affected by the main roads and subway trains, making the conditions for laying foundations complex. I hope to survey it soon as many people pass through the cemetery on their way to school or university.”