Earthquakes and nuclear /process safety

Our prayers are with the victims of the Japan earthquake. A BBC news article mentions the following:

"Japan's prime minister has declared a "nuclear emergency" after a number of reactors shut down in the wake of a massive earthquake hitting the country.Eleven reactors at four nuclear power stations automatically shut down, but officials said one reactor's cooling system failed to operate correctly.
Under Japanese law, an emergency must be declared if a cooling system fails.
In total, the country has 55 reactors providing about one-third of the nation's electricity.
In a statement, the Japan Atomic Industrial Forum released a statement that said Prime Minister Naoto Kan had declared the emergency "in case prompt action" had to be taken, but added that "no release of radioactive material" had been detected.
"Since emergency diesel generators at the Fukushima-1 and -2 NPPs are out of order, (energy company) TEPCO sent the emergency report to Nisa. There is no report that radiation was detected out of the site."
The reactor at the Fukushima Daiichi power station that triggered the emergency alert was the 40-year-old Reactor 1, one of six on the site.Reactors 1, 2 and 3 automatically shut down when the Magnitude 8.9 quake shook the plant, while reactors 4, 5 and 6 were not in operation as they were undergoing scheduled inspections.
It is understood that the earthquake cut electricity supplies to the power station, and the back-up generators did not come into operation when the outage occurred. As a result, not all of the cooling systems were available".
Obviously something happened to the back up generators and they could not come in line. We have to wait for the investigation report to come out.
Read the BBC article in this link.
Read an article about the seismic zoning in India in this link.