In Eilat, on the gulf's bay, a 67-year-old Israeli from Safed died of a heart attack after he carried his wife, who couldn't walk, down two flights of stairs. The quake was also felt in Egypt, Jordan, Saudi Arabia, Lebanon and Syria.
The earthquake was the strongest in the Jordan Rift Valley since a 1927 temblor killed 200 people in Jericho. A powerful quake also badly damaged Safed, in northern Israel, in the 19th century.
Reports on the magnitude of the temblor varied. According to Israel's seismological center, it measured 6.2 on the Richter scale.
But an official at the U.S. National Earthquake Information Center in Colorado reportedly said the measurement was 7.2, noting that the number could change.
A quake of magnitude 7 on the Richter scale is considered a major earthquake that can cause widespread, heavy damage.
Resort towns along the gulf were among the hardest hit. At least seven hotels and 50 buildings in Eilat were damaged. Water pipes burst and sidewalks cracked.
At least 15 people were treated in Eilat for light injuries and shock.
Hundreds of tourists visiting the popular resort town were roused from their beds as walls swayed and furniture and appliances crashed to the ground. They were evacuated from their rooms as building engineers assessed the damage.
Some hotel guests, who were evacuated to pool areas, reportedly donned tallitot and prayed.
At least two aftershocks continued throughout the day. The Eilat municipality and the Israel Defense Force were on alert to deal with a possible second earthquake.
Because the earthquake was centered under the sea floor, its impact was apparently lessened.
Other deaths reported in the region included five people killed in Egypt, three of them when a hotel collapsed in the resort Nuweiba. Two others in Egypt died after jumping from the balconies of their apartments. Some eight buildings reportedly collapsed in Cairo.
In the Jordanian port city of Aqaba, several miles across the Red Sea from Eilat, a Jordanian man died of a heart attack.
A statement from Saudi Arabia said two women died as a result of the quake. A 5-year-old boy and a man also may have died there.