The earthquake in Japan last week and its devastating results have once again renewed the debate regarding the preparedness in Israel for a major quake - that geologists claim is only a matter of time.

Big quakes tend to hit Israel every 80-100 years. The last significant quake was in 1927, so the next one could be imminent.

Since the early 1990s, there has been an improvement in building standards, but official sources claim that, still, at least half the buildings in Israel are not prepared to withstand a major quake and much of the communications and transport infrastructure is vulnerable.

In addition to earthquakes, there is also a risk of a tsunami on Israel's shores. While prevalent in the Pacific, tidal waves in the Mediterranean are rare, and only one case was recorded in the last century, of a relatively small one in 1956 caused by a quake in the Aegean Sea. Despite this, Israeli geologists believe that a major quake in the eastern Mediterranean could create a major tidal wave that would come crashing down on the coastal region.

The third major risk is the damage to nuclear power plants, becoming the major concern in Japan.

Israel's nuclear programme has always been secretive and there is little information on the safety arrangements of the two reactors, at Soreq River and near Dimona in the Negev desert.

In a rare interview this week the deputy director general of the Israeli Atomic Energy Commission said: "The reactors in Israel are 100th the size of those in Japan and the cooling systems are much simpler. We are taking all necessary measures to ensure their safety."

In recent months, National Infrastructure Minister Uzi Landau has called for the building of a new nuclear energy plant in the southern Negev. But at Sunday's cabinet meeting, Prime Minister Benjamin Netanyahu sounded more sceptical. "I used to be very much in favour of building civilian nuclear energy plants in Israel," he said, "but in light of what happened in Japan, we should rethink that. We are a small country and any environmental disaster here could cause much more damage than in Japan."