WANA (Dec 27) – Following a mild earthquake that shook parts of northeastern Tehran province this morning, a leading seismologist has assessed the likelihood of a larger following event as statistically minimal.

 

Morning Tremor Details

At 9:52 AM local time, a 3.3-magnitude earthquake struck near the town of Arjmand, located in the northeastern reaches of Tehran province. According to the Iranian Seismological Center, the quake occurred at a depth of 7 kilometers. While minor, the tremor was felt in Pardis and several other districts in northeast Tehran.

 

Expert Analysis

Mehdi Zare, a professor at the International Institute of Earthquake Engineering and Seismology, clarified that the epicenter was situated approximately 140 kilometers east of Tehran city, on the eastern segment of the Mosha Fault.

 

Professor Zare compared today’s event to a significant historical precedent: a 5.9-magnitude quake that hit Arjmand on January 20, 1990. “That earthquake shook the entire central and eastern Alborz region,” Zare noted, recalling his own experience feeling the vibrations from 130 kilometers away while a student in Tehran.

 

Risk Assessment for a Large-Scale Event

Addressing public concern regarding whether this morning’s tremor could be a “foreshock” for a major catastrophe, Professor Zare provided a data-driven outlook:

 

  • For a Magnitude 5.0+ Quake: The probability within the next three days is estimated at only 0.02 to 0.05.
  • For a Magnitude 6.0+ Quake: The probability is even lower, calculated at approximately 0.01.

 

“Empirical data suggests the chance of this being a foresock for an $M \ge 6$ event in the coming days is very low,” Zare emphasized.

 

Long-Term Implications

While the immediate risk is low, Zare noted that the Mosha Fault remains a significant geological feature. He explained that the fault’s behavior—characterized by left-lateral strike-slip movement—mirrors other major faults in the region, such as the North Tehran, Kandovan, and Lar faults.

 

Regarding the fault’s potential, Zare stated, “Given that the 1990 quake reached 5.9, the maximum magnitude for this segment could range between 6.2 and 6.5. However, the 35 years passed since then is likely only a fraction of the average return period for a major magnitude 6 event.”

Milad Tower at night - Tehran - Iran - Majid Asgaripour / WANA News Agency

Milad Tower at night – Tehran – Iran – Majid Asgaripour / WANA News Agency