Two minor earthquakes rattled northern Israel on Tuesday, bringing to six the number of such incidents in less than a week, a spokeswoman for the Israel Geophysical Institute said.
The most recent quake by the town of Meron in northern Israel had a 2.2 magnitude, which is very weak, she said, noting it was unrelated to a 3.3 tremor earlier on Tuesday that had its epicentre on the northern shores of the Sea of Galilee.
There were no immediate reports of damage or injuries from Tuesday's quakes.
The spokeswoman also said that since the morning's quake in the Sea of Galilee, the institute had detected four very minor aftershocks, all measuring less than 2.
On Sunday, two mild tremors were registered, one which hit just before midday (0900 GMT) and measured 3.6, while a second registering 3.5 was felt some four hours later.
Both epicentres were on or near the northern shores of Galilee.
In the early hours of Saturday morning, another quake measured 3.6. The first quake struck on Thursday evening and measured 3.5, officials said.
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Experts have so far been unable to explain the sudden increase in quakes, but the development has prompted the Israeli government to begin a national drill for earthquake preparedness.
"Following four earthquakes in the past few days, the prime minister has ordered emergency drills in schools and instructions to be given to the public," Prime Minister Benjamin Netanyahu's office said on Monday evening.
Eli Yishai, who heads the parliamentary committee charged with home front preparedness, announced a "special meeting" on Monday "in wake of the wave of earthquakes."
"We must be prepared for any scenario," said Yishai, a member of the Shas party.
The Sea of Galilee, the Jordan Valley and the Dead Sea all lie close to the seismically-active Afro-Syrian rift.
The last notable quake, a 4.2 magnitude tremor, was registered in Israel and the Palestinian territories in August 2011.
In 1927, about 300 people were killed when a quake hit Jerusalem and nearby Jericho.
A similar quake in 1837 measuring 7.0 and with an epicentre in the Hula Valley, which today lies in northern Israel, devastated the town of Safed and killed some 4,000 people.