Dr. Muhammad Mahtab Hossain Mazed

Everyone is more or less afraid of earthquakes. Many people in Bangladesh may also suffer from the damage caused by the earthquake in beautiful Turkey. It can be said with certainty that the impact of that earthquake will not fall on Bangladesh. The earthquake originated from an underground fault in Anatolia, Turkey. The fault, which is about one and a half thousand kilometers long, is quite active. Scientists and researchers had already informed the possibility of such a strong earthquake from there.

However, it is more important to be aware of earthquakes than to panic about them. Adhering to proper building codes while constructing a building is important, especially knowing what to do to avoid earthquake damageEarthquake is the shaking of the ground. Earthquakes occur when one rock moves on top of another within the Earth.

An earthquake is a sudden change in position or movement of a part of the earth's surface. If something in the house suddenly begins to sway—for example, a wall clock, hanging pictures, or any other furniture including the bed—an earthquake should be understood. In simple words, earthquake is the shaking of the earth. Dr. MM Majed, a prominent researcher of Bangladesh wrote a column about today's issue. In his column, Earthquake is a natural disaster, which scientists have not yet figured out how to predict.

In the main cities of our country, along with the increase in population, residential and non-residential buildings are also increasing. But the quality of those structures, whether they will survive a major earthquake or not, is highly feared. Our big cities don't even have the open spaces needed as safe shelters in disasters like earthquakes.

There are complaints that building codes are not followed in the construction of buildings in the country. As a result, even moderate earthquakes can cause severe disasters. And a large earthquake can cause a terrible human disaster. Therefore, in order to save from the disaster of earthquake, all kinds of structures should be made suitable for dealing with this disaster.

An average of 6,000 earthquakes occur around the world every year. Most of them are subtle, which we don't notice. There are generally three types of earthquakes—major, moderate and mild. According to the depth of the source, earthquakes can be divided into three categories—shallow, intermediate and deep earthquakes. If the epicenter of the earthquake is within 70 km of the earth's surface, it is classified as shallow, between 70 and 300 km as intermediate and below 300 km as deep earthquake.

> Why do earthquakes happen?

When underground gas escapes through fissures in the earth's surface or through volcanic vents, the gas space is vacated and the pressure on the Earth's surface exerts pressure on the space to maintain equilibrium. It is then that strong tremors are felt on the earth's surface known as earthquakes. Earthquakes are generally caused by three main causes—sudden changes in the earth's surface, volcanic eruptions, and landslides.

> Earthquake stability

Earthquakes usually last a few seconds. But this can cause massive destruction in a few seconds. According to the magnitude of the earthquake, there is massive loss of life and damage. The instrument used to measure the magnitude of an earthquake is called the Richter scale. Units on the Richter scale range from 1 to 10. A level greater than 5 on this scale means that there is a threat of severe disaster. A one degree increase in earthquake magnitude can increase from 10 to 32 times. Earthquake magnitude on the Richter scale—5 - 5.99 is moderate, 6 - 6.99 is severe, 7 - 7.99 is severe and 8 is extremely severe.

> Earthquakes in Turkey and Syria:-

The death toll from the worst earthquake of the century in Turkey-Syria is approaching 10,000. 7 thousand 108 people lost their lives in Turkey alone. And 2 thousand 470 deaths have been reported in Syria so far. The death toll in the two countries is 9,578.

Almost 60 hours after the earthquake, the rescue work is still going on. Many people are still believed to be trapped under the rubble. Moreover, there have been reports of disruption of rescue operations due to adverse weather conditions.

In the meantime, the World Health Organization (WHO) has warned that the death toll may exceed 20,000.
Now the rescue work is going on in the ruins. Many more people are trapped under thousands of collapsed buildings. Many trapped people are screaming for help from under the rubble.

Earlier on Monday (February 6, 2023) at 4:17 am local time, a 7.8 magnitude earthquake hit the Turkey-Syria border region. At that time most of the people of both the countries were in deep sleep.

Then a 7.6 magnitude and several aftershocks rocked a region of Syria. In addition, at least 10 cities in Turkey were destroyed. In the meantime, President Recep Tayyip Erdoğan has issued a three-month state of emergency in these cities.

According to US Geological Survey, the earthquake was felt in Turkey, Syria as well as Cyprus, Lebanon, Israel and Egypt. Within a few hours, hundreds of aftershocks with a magnitude of 7.5 hit the region.

Earthquakes in Turkey and Syria have killed thousands and injured thousands more.

This earthquake is considered to be one of the worst earthquakes in the world in recent times.

Scientists say that this terrible earthquake was created when the Arabian plate under the ground of the area moved northwards and pushed against the Anatolian plate.

For the same reason, an earthquake occurred here in 1822. This area of Turkey is one of the areas of the world that have been identified as being prone to earthquakes.

> How do earthquakes occur?

"The Earth's crust is made up of separate bits, or plate tectonics, that float on top of the soft material below. There are seven major such plates and numerous smaller sub-plates all over the Earth. "

"When they move or move or push against each other, elastic energy is stored within the geology." When it exceeds the rock's carrying capacity, the energy is released through existing or new cracks. Then tremors are created on the earth's surface, that is the earthquake.

The places where one plate comes into contact with another plate or pushes or cracks are called fault lines.

At present the vice chancellor of Ummukt University Mr. Akhtar says, “Where the plate boundary is formed, we call it a fault line. Its surrounding countries are most prone to earthquakes.

The United Nations launched a program called the Global Seismic Hazard Assessment Program to identify earthquake-prone areas of the world. Its purpose was to create a map of the world's earthquake-prone regions, to help prepare to avoid damage.

Under that project, the world was divided into regions based on data and research on past earthquakes. Currently, the areas of the world that are of particular interest to scientists are:

> Bangladesh

Geological experts say that these areas are at great risk of earthquakes due to the presence of several plates in the Sylhet to Chittagong region of Bangladesh.

Syed Humayun Akhtar, a former professor of the Department of Geology at Dhaka University, says, "Bangladesh is located at the intersection of the Tibetan sub-plate in the north, the Indian plate and the Burma sub-plate in the south. As a result it went to South Sumatra via Sylhet-Sunamganj, Kishoreganj via Chittagong.

It has been observed that no seismic energy has been released for a long time at the junction of the India plate and the Burma plate. As a result, energy has accumulated there for 400 to 1,000 years.

The India plate is subducting under the Burma plate towards the east and the Burma plate is subducting towards the west. As a result, the amount of energy accumulating there can cause more than eight magnitude earthquakes.

As it can happen once, it can happen several times. However, they fear that a major earthquake may occur at any time. Usually, in such cases, there are earthquakes of magnitude seven or eight. But when or when that will happen, scientists still have no idea.

The last major earthquakes in Bangladesh occurred in 1822 and 1918 on the Madhupur fault. A 7.5 magnitude earthquake is recorded in Manikganj near Dhaka in 1885.

> India and Nepal

The world is divided by many tectonic plates. When these plates move, earthquakes occur in the countries or areas that lie on top of those plates.

Nepal sits on the tectonic plate at the foothills of the Himalayas, on which lies the northern part of India.

British Geological Survey official Roger Musson told BBC Newsbeat, "Any earthquake there could be worse than Saturday's earthquake in Turkey."

Cities like Kathmandu in particular are at particular risk. Because the city is built on a thick layer of soft rock. As a result, if there is an earthquake, the vibration will be felt more.

In 2015, the collision of the Indian plate and the Tibetan plate caused a terrible earthquake. More than 9 thousand people died and more than 100,000 people were injured in that earthquake.

> Turkey

Turkey is another country that has suffered a number of devastating earthquakes in recent times.

The North Anatolian fault line runs across most of Turkey from east to west.

There, the Arabian Plate moved northwards and pushed the Anatolian Plate, causing the most recent earthquakes.

A part of Istanbul in particular is the center of this fault line, where the two plates often rub against each other and fluctuate at different times.

As a result, earthquakes occur occasionally in this area.

In 1822, a terrible earthquake of 7.4 magnitude occurred in this area.

> Iran

Tehran, the capital of Iran, sits on another active fault line, the Arabian Plate.

John Elliott, a researcher at the University of Oxford, said, "This city sits on the very top of a fault line. The fault line has moved several times in recent times and may cause earthquakes in the future as well.

In 2003, an earthquake of magnitude 6.6 occurred near the city of Bam, Iran, killing 26,000 people and injuring many more.

This fault line in Iran runs from the eastern shore of the Black Sea to the southern coast of the Caspian Sea.

> China

China is at risk of major earthquakes due to the collision of plates between India and Eurasian.

In 2008, the Wenchuan earthquake killed 90,000 people. Around 5 million people lost their homes at that time.

"The seismicity here is a bit shallower, so stronger tremors are more intense," said Liverpool University seismologist Stephen Hicks.

Experts say that despite the risk of earthquakes, houses in those areas are not built earthquake-resistant. As a result, after an earthquake occurs in such areas, the damage is more and there are many problems in the rescue work.

An earthquake of magnitude 806 occurred in Tibet in 1950, although exact damage is not known.

> Japan

Scientists have long feared that a major earthquake could strike near Tokyo. However, the Japanese have prepared well.

The tsunami that hit Tokyo in 2011 killed more people than the earthquake itself.

Scientists say several tectonic plates are colliding deep beneath the city of Tokyo. Especially on the western side of the Pacific Plate lies Japan. As a result, when these plates move, earthquakes are felt there.

Japan records the most earthquakes of any country in the world.

> Indonesia
Countries like Japan, Indonesia, Fiji and Tonga record small earthquakes every year.

Because the Australian plate is wrapped around the Indonesian archipelago. Its part is also special in Japan.

When a magnitude 9.1 earthquake hit the west coast of Sumatra in 2014, it set records and triggered the largest tsunami in history. More than two lakh people died in that tsunami.

In addition to Indonesia, Japan, the Philippines were victims of that tsunami.

> Europe

According to the Global Seismic Hazard Assessment, Turkey and parts of the surrounding Mediterranean Sea are at high risk of earthquakes.

This is because earthquakes occur here as the African continental plate pushes up the Eurasian plate beneath the Adriatic Sea. Due to this, earthquakes are also seen in central Italy and western Turkey.

In 1955, Lisbon, the capital of Portugal, experienced an earthquake of magnitude 8.7, a record for the region.

In 2016, three moderate earthquakes in Amatrice, Italy killed more than 300 people.

> in Nepal

In the 2015 earthquake in Nepal, many houses in the capital Kathmandu collapsed.

> USA and Canada

Northern California, Oregon, Washington and part of Canada lie near a major fault line.

In this fault line, two plates collide against each other. These two plates are the Juan de Fuca plate or the Pacific plate and the North American plate.

Major cities located around these fault lines are at high risk of earthquakes. These include Los Angeles, San Francisco, Seattle and Vancouver.

"This fault has been quiet for quite some time," says researcher Stephen Hicks of the University of Liverpool.

However, he said, after the 2011 tsunami in Japan, major research is being done on how severe this fault can become.

In 1964, a powerful 9.2 magnitude earthquake struck Alaska.

> Chile

Due to the collision of several continental plates with the South American plate, strong earthquakes are often seen in South American countries.

The Caribbean coast of Colombia and Venezuela in particular is an earthquake prone area.

The largest earthquake recorded in this area was in 1960. At that time, a magnitude 9.5 earthquake near Salvador, Chile killed more than 5,000 people. More than 2 million people were displaced.

Then in 2010, another 8.8 magnitude earthquake occurred near the city of Concepcion. About 500 people were killed in the service. Chile's capital Santiago was also heavily damaged in that earthquake.

Apart from this, there have been several earthquakes, which were not expected by scientists or researchers.

For example, it was only after the 2011 Christchurch earthquake in New Zealand that scientists first learned that there was a fault line under the city.

What to do during an earthquake

• If you feel or hear about an earthquake, immediately take shelter in an empty and open place.
• 
   If you are in a tall building and can't get out, stay under a strong beam or table instead of next to a window or wall.
•  Deal with the situation patiently without panicking.
•  In multi-storied buildings, many people should not stay together in the same place and take shelter separately.
•  Keep fire services and useful mobile numbers in your mobile phone as early warning. You will be useful in times of danger.
•  Do not jump off buildings to get down quickly.
•  During an earthquake, if possible, hold a pillow or other solid object [cardboard, roll of soft cloth] firmly over the head.
•  Keep away from gas and electrical connections.
• Do not use elevators to get down quickly from tall buildings.
• If you are in a car during an earthquake, stop the car in an open place and stay in the car.
• Once an earthquake is followed by another smaller earthquake which is called an 'aftershock'. Keep yourself free from danger. Therefore, to keep earthquake damage to a minimum level, mass awareness should be developed in this regard. The government has to play the main responsibility in this regard, so that the potential damage is kept to a minimum level. From the beginning of the construction of a building to the end, whether the concerned person or organization is following all the rules must be strictly monitored. Finally, I want to say, people are for people. May your humanity shine through in times of danger. Ensure your own safety and extend a helping hand to your neighbors. Along with protection from danger, one should try to face the danger with courage without being afraid. It is difficult to say how much damage can be contained in a major earthquake, but preparedness will help to cope. Our ability to do logistical damage control at the national level may be woefully inadequate. But if the above guidelines are followed individually or collectively, the incidence of loss of life or injury can be greatly controlled. People for people. May your humanity shine through in times of danger. Ensure your own safety and extend a helping hand to your neighbors. Along with protection from danger, one should try to face the danger with courage without being afraid. It is difficult to say how much damage can be contained in a major earthquake, but preparedness will help to cope. Our ability to do logistical damage control at the national level may be woefully inadequate. But if individuals or groups follow the above guidelines, the incidence of loss of life or injury can be greatly reduced.

The writer is a columnist & researcher Founder Chairman, Jatiya rogi Kalyan Society