Israel held its first major earthquake drill on Sunday, stepping away from simulated Iranian missile salvoes though officials insisted the country remained ready for any war with its arch-foe.
Schoolchildren, civil servants and others participating in the annual "Turning Point 6" exercise were urged to flee outdoors if possible when tremor alerts were announced on radio and television - a departure from previous years when they would congregate in bomb shelters.
The change in format comes during a respite in the hostile rhetoric over Tehran's disputed nuclear programme, with both Israel and the United States about to hold elections and Western powers pursuing ever-harsher sanctions against the Iranians.
But Israeli officials denied that the drill signalled an easing of their Iran posture, describing earthquakes as a credible separate threat given the abutting Syria-Africa rift.
"We understand that earthquakes will certainly happen. The question is when," Mickey Tessler, a brigadier-general in Israel's military Homefront Command, told Army Radio.
He added: "It is very important to emphasis that whoever is ready for earthquakes perforce increases his readiness level for various events, including wartime events."
Turning Point 6 was to feature simulations of 5.4- and 7.1- scale tremors as well as a tsunami drenching Israel's coast, where most of its population and industry is centred. Israelis on the lower floors of buildings were instructed to find safe ground outside, and those on higher storeys to shelter in fortified rooms or under sturdy furniture.
The exercise coincided with Israeli-hosted joint missile-defence manoeuvres with U.S. forces. That three-week drill, "Austere Challenge 2012", is unrelated to Turning Point 6, an Israeli military spokeswoman said.
Israel has hinted it could resort to military force to deny Iran the means to make nuclear arms - which Tehran denies seeking - and has made similar threats to attack Syria's chemical arsenal. Either action could draw retaliatory missiles against the Jewish state from Iran, Syria and Islamist guerrillas in Lebanon and Gaza.