In this site (published on 6 November 2001) I found the following information:

Historical data suggest there is a major earthquake in Tehran every 158 years and the last one there was in 1830.

The 1990 Manjil-Rudbar earthquake occured 160 years after the last major earthquake in Tehran, just 2 years after reaching the 158 years interval.

Can we say the 1990 earthquake postponed a major earthquake in Tehran for another century?

It's true that the fault that caused the 1990 earthquake differs from the fault that caused the 1830 one; but the epicenters are close in a geographical sense and the seismic energy of the Earth got evacuated well in the region after the 1990 earthquake.

There was alao a 5.2 magnitude earthquake near Tehran on 2017-12-20; but that can't be counted a major earthquake. The 1830 earthquake had a magnitude of 7.1.

P.S. I don't know if evacuated is a good word here.


1 Answer 1


Statements such as:

Historical data suggest there is a major earthquake in Tehran every 158 years

should not be interpreted as a number without variation. It is an average number of years. What the statement doesn't state is the error range for the 158 year time period.

Additionally, such a statement is a very general statement. The statement doesn't state which locations in Iran this applies to, or which fault or faults it applies to. One cannot draw to many conclusions from it.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.