Robert Muir-Wood, chief research officer for risk modeler Risk Management Solutions, told NU Online News Service that for some models tsunamis are a "deterministic footprint," but are not generally a part of catastrophe modeling.

The earthquake and tsunami in Japan will "very likely" make tsunamis a fundamental part of catastrophe modeling in the future, he said.

There are two reasons why tsunamis, especially in Japan, were not a part of catastrophe models, Mr. Muir-Wood said. First, the government has spent a lot of money on sea walls that were thought to protect the populace from such an event. But the recent event "came clear over the top."

Second, the area of concern was with Tokyo bay, where it was thought a tsunami would not be a significant problem.

"People believed that this was not such a big risk," he said.

For modeling purposes, tsunamis would only be a concern if they were an extreme loss event, noted Mr. Muir-Wood, and this particular event was not only extreme, but very rare. The last such tsunami of this magnitude in Japan was recorded 1,100 years ago.

As for nuclear catastrophe modeling, it is not an insurable event for core insurers, he noted. However, there are lessons to be learned from the reactor failures in Japan from a risk modeling perspective, said Mr. Muir-Wood, and it is an area that RMS might get into in the future, but not one that would be the focus of an insurable risk.

For insurance, executives insuring nuclear risks said that earthquake and tsunami risks are excluded from coverage.

As for the status of the nuclear plants in Japan, the International Atomic Energy Agency said today that there were explosions in three nuclear reactors at the Fukushima Daiichi nuclear plant in Japan. Three other reactors at the site were shut down for maintenance before the tsunami.

Elevated levels of radioactivity were detected in the area and an evacuation of a 20 kilometer zone (12.5 miles) was put into effect. People within a 30 kilometer (19 mile) radius of the plant were advised to take shelter indoors.

A 30 kilometer (19 mile) no fly zone was also established around the plant, the IAEA said.

The IAEA said a 6.1 magnitude earthquake was reported around 13:31 UTC (8:30 a.m. EDT)  in Eastern Honshu, Japan. The Hamaoka nuclear power plant is located about 100 kilometers (62 miles) from the epicenter of that earthquake. The plant operates safely, the IAEA said.