MISAWA AIR BASE, Japan - While the world focuses on the devastation in Haiti, millions of people in Japan — including tens of thousands of U.S. troops and their families — sit on their own seismic time bomb.

Officials say it’s not a question of if, but when, a massive earthquake will rock the country.

"Japan is a land of earthquakes," said Hiroshi Araya of the Japan Meteorological Agency’s earthquake prediction information division. "It could happen anywhere."

Japan sits on four tectonic plates — the North American, Eurasian, Philippine Sea and Pacific — that constantly crush against each other. It’s a perfect recipe for massive quakes, and even with the best technology, nobody knows when the next one will strike.

"[It] could occur somewhere in Japan tomorrow," Araya said.

Between 1996 and 2005, there were 912 earthquakes worldwide registering 6.0 or greater on the Japanese seismic intensity scale. Of those, 190 — nearly 21 percent — hit Japan.

Japanese officials are focusing much attention on what they’ve already named the Tokai earthquake, which they believe could hit the Nagoya region any time.

The last quake on that fault line — the Suruga Trough — occurred in 1854. Since major quakes tend to happen there every 100 to 150 years, experts say the Tokai quake is overdue.

The greater Tokyo metropolitan area — home to four U.S. military bases — suffered its most recent massive quake in 1923. The Great Kanto earthquake killed an estimated 140,000 people and destroyed more than 680,000 buildings because of the fires that raged throughout the city.

Even with technological advances and new construction standards, officials say thousands would die if a 7.3-magnitude earthquake were to hit Tokyo with an epicenter in Tokyo Bay.

In 2003, Japan’s Central Disaster Management Council published predictions that as many as 11,000 people could be killed and 85,000 buildings destroyed, depending on the time of day and wind strength. About 1 million people would be without water, 1.6 million households would lose power and 1.2 million would lose gas, according to Japanese officials. They also predict that as many as 7 million people would be forced to evacuate the city.

In 2005, the Japanese government launched an initiative to lower those numbers by providing aid or tax breaks for work to strengthen homes and buildings against the quakes and by working on improving Tokyo’s clogged roadways to enable better emergency response.

Responders learned lessons from the Great Hanshin earthquake that rocked urban Kobe on Jan. 17, 1995. That quake killed more than 6,000 people, and news reports showed scenes of devastation, including images of a section of city highway that tumbled onto residents living in streets below because they were terrified of aftershocks. According to news reports, some 200,000 buildings were destroyed.

Each year, the U.S. military joins in Tokyo region disaster management drills, held Sept. 1, the anniversary of the Kanto earthquake.

Troops and their families say Haiti served as a good reminder of the chaos earthquakes can create. They said having a stock of essential items is important.

Tech. Sgt. Paul Poggenpohl and his wife, who live on Yokota Air Base near Tokyo, maintain an earthquake kit that includes water, batteries, radios and protective masks.

"People can take things for granted sometimes, so it’s important to be prepared," he said.

Jennifer Casey, a Navy spouse at Yokosuka Naval Base, said she keeps extra food and water on hand. But she’s a bit worried about how her off-base home would fare in a big quake.

"I don’t know that it would [hold up], honestly," she said. "But I hope it was built to withstand a strong one."

Senior Chief Petty Officer Chris Royal said his family always has an emergency kit with flashlights, a first-aid kit and extra money in case something happens.

Royal was part of a Navy relief team after an earthquake struck San Francisco in 1989.

"It’s important to always know where your safe areas are and exit points from your house or buildings," he said.

Royal lives in one of Yokosuka Naval Base’s tower apartments, which he and officials say can withstand a strong quake.

"This area is susceptible to earthquakes, so I think the towers were built with that in mind," Royal said.

Military officials said base housing and office spaces in Japan are constructed in accordance with strict Japanese standards.

Officials have said that all buildings constructed after 1981 meet the current standards.

------------------------------------------------------------------------------------------------------------------------

Earthquake Survival Tips

During an earthquake and its aftershocks:

• Inside — Take cover under a desk or table, or against an inside wall. Protect your body from things that could injure you. In bed, cover yourself with pillows and blankets.
• Outside — Move away from buildings, trees, billboards, telephone and electric lines.
• In a car — Drive away from bridges, underpasses and overpasses; stop in a safe area; stay in vehicles until shaking stops.

After the shaking stops:

• Check for injuries.
• Check for gas, water and sewage breaks; check for downed electric lines and shorts; turn off appropriate utilities; turn off gas only if you see, smell or hear gas escaping; check for building damage and potential safety problems such as cracks around chimney and foundation.
• Wear sturdy shoes.
• Don’t use the telephone except for life-threatening emergencies.
• Tune in to local radio station.

Supplies to have on hand:

• Portable radio with extra batteries
• Flashlight with extra batteries
• First-aid supplies, including an extra pair of glasses and a first-aid book
• Fire extinguisher, A-B-C type
• Smoke alarm
• Portable fire escape ladder for homes/apartments with multiple floors
• Bottled water — at least one gallon per person per day
• Canned and processed foods sufficient for a week for each member in household
• Non-electric can opener
• Portable stove such as butane or charcoal. NOTE: Do not use stoves until you are sure there is no gas leak nearby. Use charcoal outdoors only — use indoors can cause carbon monoxide poisoning.
• Matches
• Telephone numbers of police, fire and doctor

Source: U.S. Air Force safety officials