Mohandes Magazine Fall-Winter Edition 2018

Life on Active Faults: Connecting the Iranian
diaspora to give hope and to help reduce, or
mitigate the effects of natural disasters
By Arsalan Mohajer, PhD., D.I.C., P.Geo.
Earthquakes don’t kill, weak buildings do – poorly constructed buildings can be viewed as ticking
time bombs, for vulnerable communities in certain active fault zones in Iran and elsewhere
around the world. A comparative review of rates of casualties’ shows destructive impact in Iran is
much higher than other earthquake prone countries that are better prepared.
Yet again, on November 12, 2017 at 16:18 local time, a magnitude (M) 7.3 earthquake devastated a
large area in the western Kermanshah province in Iran, near the Iraq border. It was the deadliest
global Earthquake of 2017.
The Energy released by a M7.3 earthquake, at 29km depth in western Iran was equivalent to 89 Hiroshima
Atomic Bombs (89 x 15 Kiloton TNT).
Local news reported over 700 dead and 9,000 injured in many villages and small towns of the province.
Luckily, the mountainous area is not densely populated otherwise the extent of the disaster
would have been much larger.
Tehran awakes with an earthquake fright on December 20, 2017, too.
Just before 11:30 p.m. local time, a M4.9 earthquake struck the west-end of the city of Tehran with a
population of 8.3 million in Tehran proper, and 14 million including the surrounding communities
(Fig. 1)
The epicenter of the 2017 Tehran Earthquake was in the Malard region just east of a M5.7 earthquake
in 1876, and northeast of Qazvin which experienced a M7 earthquake in 1962. Such a storied past
indicates that the Tehran region is within an earthquake hazard zone and that another major earthquake
is overdue. There are history of five damaging earthquakes in old city of Rey to the south, in
addition to statistically significant recorded events since early 20th century in Tehran region. Therefore,
probabilistic estimates of M7 earthquakes suggest a return period of 170-200 years. Nonetheless,
based on deterministic evaluation of active faults in the region such occurrence is inevitable,
and needs to be incorporated in design of the built environment.
The over-due event in Tehran region could kill in hundreds of thousands, and could cause over a
million-population displacement. Some of the main reasons for such calamity are; extensive vulnerability
to old and weak buildings, relative complacency with enforcing building codes and soft soilstructure
interaction at the southern part of the city, limited open spaces for rescue and recovery,
and lack of preparedness drills at schools, offices and homes.
30 MOHANDES MAGAZINE