The precise determination of tremors that rattled Mazandaran province also needs further studies, Director for Public Training of Earthquake Research Center, Farokh Parsizadeh told IRNA.
He further refuted rumors on the predictability of the precise occurrence of earthquakes.
"No expert is able to determine the timing of tremors, which is practically impossible. Any assertion in this regard is completely false," he added.
There is no danger threatening the capital city, but the residents, if they feel more comfortable, can spend time outside their homes, Parsizadeh said.
He said three teams with the aim of assessing the damage have been dispatched to quake-stricken areas.
The seismological base of Tehran University's Geophysics Institute said quakes, measuring from 1.6 to 5.5 on Richter scale, hit Baladeh region in the northern province of Mazandaran 65 times during 12 hours.
A powerful earthquake, measuring 5.5 degrees on the Richter scale, struck vast parts of Iranian northern cities at 17:08 hours local time (1238 GMT) on Friday. The quake also shook the capital Tehran.
The quake has killed at least 20 people, injured 200 others and damaged scores of villages of 30 to 100 percent.
Eleven of the dead were occupants of over 60 cars which were buried under falling rocks on a mountain road that crosses the Alborz Mountain chain between Tehran and Chalus on the Caspian Sea coast, governor of Kelardasht District, west of Mazandaran, Hossein Ali Golalizadeh said.
He did not give the exact number of those killed but said "many" people have been killed.
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