Media Guide: Earthquakes in Iran
/By Research Associate Lauren Elmore
Iran is an extremely earthquake-prone country. These natural disasters have caused the country tragic loss of life and hundreds of billions of dollars in infrastructure damage. Over time, the Iranian government has implemented some mitigation efforts to limit damage, however, these efforts have not been sufficient, and regulations remain unenforced due to economic turbulence.
What causes earthquakes, and how are they classified?
Earth’s outer shell, the crust, is divided into major “plates”, or large, often irregularly shaped segments of the lithosphere. Underneath the crust is the mantle. This is a heated layer of the earth, with temperatures ranging from 1,000 ºC to 3,700 ºC. Because of these high temperatures, the underside of the earth’s crust, or the plates, are warmed, resulting in them becoming malleable and movable. This movement is often referred to as the plate tectonic theory. During movement, the edges of the plates can hit or slide against one another, which is responsible for the creation of many geographical features such as mountains and oceanic trenches. Unfortunately, despite the wondrous geographic landmarks that have emerged across earth due to the shifting of tectonic plates, destruction may follow.
As these plates slide past one another, friction is generated, and sometimes plates get stuck on each other. When enough pressure produces what is known as elastic strain, eventually this frictional force is overcome, and energy is released as the plates break free from one another. The energy is released in seismic waves, causing an earthquake. In this process, a nearby individual will often feel a sharp jolt due to the pressure releasing and extended and violent shaking caused by the seismic waves. These are commonly referred to as tectonic earthquakes. Though there are other types of quakes, such as volcanic, collapse, and explosion earthquakes, tectonic quakes are by far the most common and well-known occurrences.
Earthquakes are categorized by severity and magnitude. The most popular scale for this is the Richter scale, developed in 1935. This scale is numerically based and primarily focused on damage caused. Earthquakes classified from 1.0-3.0 on the scale typically do not cause damage to nearby infrastructure or landscapes. At 4.0, there is some damage reported. At 5.0, earthquakes can cause damage to buildings with poor construction, and the shaking can be felt across the zone. Then, at 6.0, the earthquake can damage most, if not all, buildings, and the quake can be felt for hundreds of miles. Upwards of this, extreme damage, including the total collapse of buildings and geographical alterations to the landscape, can occur. Many other scales have since been developed, such as the Modified Mercalli Scale, the Moment Magnitude Scale, and Earthquake Magnitude Classes, to name a few. More recently, technologies such as seismograms were created and used to measure the wavelengths of the seismic waves that are dispersed during an earthquake.
Why is Iran so prone to earthquakes?
The connecting edge of tectonic plates is known as a fault zone, characterized by its high strain slip surfaces. There are multiple fault lines across the globe, each containing an increased risk of seismic activity. Between Iran and Iraq, the Arabian and Eurasian fault line stretches as the two tectonic plates meet. While this fault line was responsible for the creation of the Zagros mountain range, it has also been the cause of a multitude of earthquakes. Though the most major fault line present within Iran, it is not the only one. Over 90% of Iran resides in an active seismic zone. Due to this, Iran is considered to be at extreme risk for earthquakes.
What is Iran’s history with earthquakes?
Because of Iran’s location over the faultlines, it is, unfortunately, no stranger to earthquakes. On average, Iran experiences one earthquake every day. From June 15th, 2021, to July 15th, 2021, Iran experienced one 5.0 magnitude earthquake, 11 4.0 magnitude earthquakes, 46 3.0 earthquakes, and six 2.0 and below quakes. In May of 2021, nearly 1,000 earthquakes occurred within the country.
Earthquakes are not a new phenomenon by any means, and since 1950, over 172,000 people have died in Iran as a result of quakes. In addition to the loss of life, billions of dollars of damage (including the Rudbar-Manjil earthquake in 1990, which alone caused almost eight billion dollars worth of destruction), has been incurred in Iran. Earthquakes have caused enormous amounts of damage to Iranian infrastructure, leveling villages, damaging schools, and destroying water facilities within Iran, each one thereby posing significant challenges to the future of many Iranians’ livelihoods and quality of life.
The strongest earthquake in Iran to date, measuring 7.8 on the Richter scale, occurred in 1978 within the Tabas region. This event resulted in over 20,000 deaths. The most deadly earthquake occurred in 1990; it was a 7.7 magnitude earthquake in northeast Iran. This was responsible for the deaths of over 50,000 Iranians and injured 135,000 others. The damage to nearby infrastructure was similarly catastrophic. Dams, farms, and roads were destroyed entirely. Over 400,000 people were left without a home after the quake.
Perhaps the most infamous quake to date, however, given the amount of destruction it caused was the 2003 Bam earthquake, measuring at a 6.6 on the Richter scale. Nearly 30,000 people were killed, and while damage occurred primarily in a 20-30 kilometer radius around the city, it was felt as far as the capital of Kerman, 190 kilometers away. Almost 90% of Bam’s infrastructure was damaged or completely destroyed. This quake was so severe, in fact, that the Iranian government considered moving the capital from Tehran, as it also resides in a highly seismic area, after the disaster occurred.
What are the implications of earthquakes in Iran?
Earthquakes have resulted in widespread problems across Iran. First and foremost, Iranian architecture and infrastructure incurs ongoing damage due to earthquakes. During some quakes, entire villages have been destroyed, with one earthquake so damaging that almost 200 villages were obliterated. The mud and clay building materials of many Iranian homes leave them extremely susceptible to total collapse during the event of a quake. Along with this, schools and water facilities have been damaged, and roads have begun to form cracks as a result of earthquakes.
Such damage has hurt Iran economically. Over the past 100 years, Iran has spent nearly seven trillion dollars on earthquake-related disasters. This money is primarily allocated towards disaster response and recovery, though some funds are distributed to mitigation and preparedness. However, economic issues also arise outside of government expenditure. For example, before the 2003 Bam earthquake, Bam was a prominent area of agriculture activity. Not only did the quake kill 12% of the area’s farmers, but it also harmed the irrigation systems within the city and damaged the production of crops within neighboring areas, resulting in an exacerbation of water scarcity in the surrounding regions. Additionally, business activity, both from small and large corporations, was frozen during repairs. Many factory workers were killed, causing some companies to shut down production for months on end. Repairs themselves were another source of economic strife. Residents of Bam who required repairs often relied heavily on loans and still could not afford reconstruction due to the increase in cost of materials. As a result, repairs took years to conduct.
Not only have earthquakes slowed down economic development, but such disasters have also decreased external funding into the country, due in significant part to reduced tourism in earthquake-affected areas. Earthquakes across Iran have halted tourism for many months due to damages in tourist locales. For example, in Bam, the Citadel is a major tourism destination, which was severely damaged. While such damage was ultimately repaired, this event altered tourists’ perceptions of the region negatively. Even a decade following the quake, tourists are still uncertain about visiting Bam.
Socially, earthquakes have also had a measurable negative impact on Iran. Though earthquakes themselves cannot be stopped or prevented, control and safety measures are conducted by the government and are oftentimes lacking. Protestors have claimed that conditions within Iran, such as the quality of housing and overpopulation, “make Iranian people vulnerable to disasters like earthquakes”. The Iranian government’s recovery responses are also criticized both by citizens and local authorities. Following a severe earthquake that impacted Northwest Iran in 2013, many officials of affected areas complained of a lack of resources, such as tents, provided by the crisis management center.
On an individual level, psychological intervention is often required and provided after earthquakes due to increased anxiety and stress related to the disaster. Often, these psychological issues are long-term problems due to the scale of the destruction and the length of time physical recovery takes. Families have been split apart as a result of these earthquakes, and communities were negatively impacted.
Earthquakes in Iran have also been used to push societal and religious standards, with “immodest women'' sometimes being blamed for these events.Hojatoleslam Kazem Sedighi, an Iranian Cleric, stated on April 19th, 2010 that “Many women who do not dress modestly... lead young men astray, corrupt their chastity and spread adultery in society, which increases earthquakes”. His statementultimately sparked a mild feminist movement on April 26th, 2010. Women worldwide dressed immodestly to spark a quake, which ignited a multitude of discussions regarding women’s rights.
What actions has Iran taken to mitigate the consequences of earthquakes?
Earthquake mitigation typically comes in three stages: prevention, control, and rehabilitation. Earthquake prevention is geared towards early detection of a seismic event. In 2017, Tehran began developing an Earthquake Early Warning (EEW) system to detect seismic activity within the city. This detection system has since evolved significantly, and studies show that it provides reliable and accurate warnings of earthquakes from 1 second to 20 seconds. While seemingly a short amount of time, this provides crucial moments for individuals to locate shelter as the quake continues.
Iran has also opted to alter its architecture in response to earthquakes, developing earthquake-resistant homes. Poor architecture and building materials have caused damage to Iranian towns and villages when faced with earthquakes, as they often lack internal resistance and support. After an earthquake in 1962, Iranian architects and scientists gathered to create the “Iranian Code for Seismic-Resistant Buildings Design”, which established codes and regulations for buildings being constructed within Iran. Other private architects within Iran have also opted to create designs to decrease damages caused by earthquakes.
Recovery tends to be Iran’s bright spot. Following the earthquake in Bam, a multitude of organizations such as the Iranian Red Crescent Society, law enforcement, and other volunteer programs were deployed to rescue injured Iranians. These groups set up temporary shelters, including 50,000 tents, 18,000 showers and latrines, and thousands of units with air conditioning and water capabilities. Though reconstruction took years, relief was provided almost immediately. The Iranian health emergency response has been deemed to be largely satisfactory, and in recent years, has increased in efficiency. Emergency responses to the Bam earthquake in 2003 took over three hours due to communication failures. Since then, responses to earthquakes have occurred more rapidly and have been a more unified front.
Iranian earthquake architecture and other mitigation efforts have proven to be invaluable. However, this does not mean that these regulations have always been followed, resulting in an increased amount of destruction within preventable areas. Perhaps one of the most well-known examples of this was the Bam earthquake. Its extreme death toll was, in part, the result of poor building regulations and low-quality construction. Professor Mohsen Aboutorabi of the architecture department at the University of Central England, Birmingham, who worked in Bam, stated that “many buildings collapse [even] without earthquakes, because of the poor construction.” The quake destroyed 15,935 residential buildings and 10,176 non-residential buildings. These material and regulation shortcuts are the result of high inflation and importation prices of construction materials, namely concrete. As prices for materials continue to increase, building contractors opt to purchase less durable yet more affordable materials, placing the future of the homes at risk.
Earthquakes have played a large role in exposing the efficiency and reliability (or lack thereof) of government response. Though countries such as Japan and Chile experience, on average, more seismic activity and a greater magnitude of earthquakes, Iran often experiences greater damage. This is due primarily to the inadequate planning and preventative measures put in place for future disasters. This is partly a government choice due to poorly enforced regulations, but also due to the poor economy, which does not allow for sufficient funds to put forth for mitigation.
What does the future pose for earthquakes in Iran?
The future of earthquakes is naturally unpredictable. Some scientists believe that quakes will grow more intense in severity and frequency due to climate change. Long periods of drought can increase the pressure on the earth’s crust and increase the number of earthquakes. Similarly, continual depletion of groundwater can also place stress on the earth’s crust. Unfortunately for Iran, periods of drought and intense water pumping have been growing issues within recent years. This does not bode well for the future of earthquakes in an already extremely seismic zone. Therefore, the frequency of earthquakes in the future for Iran is unlikely to decrease and may, in fact, increase.
With mitigation efforts and new technologies, these earthquakes will likely become less destructive, however. An increase in the number of earthquakes has actually allowed for a better understanding of the tectonic plate makeup under Iran and Iraq, aiding in future estimation and prediction models. However, rapid urbanization, an issue that has plagued Iran for years, could prevent further progress in this area. Detection of earthquakes has grown more complicated as urbanization increases across the country. Large numbers of buildings and skyscrapers have been built, obscuring previously detectable signs of potential earthquakes across cities like Tehran. Nevertheless, technology is continually advancing.
