next five important earthquakes

20 10 2009

Interesting article in Time today:,28804,1930622_1930614_1930606,00.html

Next five major (important) earthquakes expected to occur in: Los Angeles, Tokyo, Tehran, Pacific Northwest, Indonesia

“All of Iran lies within a major earthquake zone, and the country has suffered terrible temblors before — most recently in 2003, when a 6.8-magnitude quake leveled the ancient city of Bam and killed more than 30,000 people. But a similar quake in the congested capital of Tehran — where more than 7 million people live — would be a shattering catastrophe. Unlike building codes in other endangered cities such as San Francisco and Tokyo, Tehran’s are relatively lax, and many residents like in the sort of unreinforced-concrete houses that turn into death traps in the event of a strong quake. The Iranian Health Ministry once estimated that a 7-magnitude quake would destroy 90% of the city’s hospitals. Tehran is so threatened that there has been periodic talk about moving the capital.” — Time, Oct. 20th, 2009

tehran’s minor earthquake on saturday

19 10 2009

Tehran experienced a minor earthquake (Richter magnitude 4) on Saturday at 2:23 pm local time ( It seems that most Tehranies felt this shake. There is now a widespread fear of aftershocks and possibly bigger earthquakes due to more activities on the Eivanaki fault in southeast Tehran. Since information on the historical activity of this fault seems to be limited, it is difficult to make accurate probabilistic predictions on the likelihood of an aftershock. But it is certainly possible and quite likely to have another earthquake soon (not necessarily related to this particular fault movement). Tehran sits on major active faults and suffers from a large seismic risk due to fault activity, poor construction practice, and large population. The occurance of this recent minor earthquake may have influenced the stresses in the surrounding faults and might have increased the existing seismic risk facing Tehran.

 tehran map

Tehrani residents, engineers, contractors, general public, please be aware and pay attention to this important risk that you will have to deal with sooner or later. To learn how to protect yourself before, during, and after an earthquake, visit this site by FEMA:

In two of our previous posts, we also had some good discussion on earthquake preparedness in Tehran:

Tehrani engineers, architects, and contractors: I assume that you already know how to make earthquake resistant structures in a cost-effective way. If you have questions/concerns, please don’t hesitate to contact me and I will try my best to send you information on the current state of practice (in structural and geotechnical design) for your specific project. If you are not convinced about the risks facing your city and need more information on the probability of earthquakes in the coming years, also please don’t hesitate to let me know or contact someone at IIEES in Tehran ( Keep in mind that you are responsible for your building, and negligence and lack of knowledge are not acceptable any more.

iran’s population density

11 10 2009

A very interesting way of graphically showing the population density, and hence the earthquake risk facing different parts of Iran (based on their vulnerability):

iran population density

understanding earthquakes and effects

6 10 2009

Great overview of our progress and current understanding of earthquakes since the 1906 great San Francisco earthquake: