Dr. Muhammad Mahtab Hossain Mazed

The sudden and temporary shaking of the earth's surface is called an earthquake. "An earthquake is a shaking of the earth's crust of the earth." These vibrations, caused by the sudden release of stored energy in underground rocks, can range in magnitude from gentle vibrations to violent rotations. An earthquake is a type of wave motion energy, which originates in a limited area and spreads in all directions from the source of the event.

Earthquakes usually last from a few seconds to a minute. Earthquake is not a new natural disaster in the history of the world. Earthquakes have been happening since time immemorial and will continue to happen in the future. People are completely helpless to these natural disasters. That's why today the thought of reducing earthquake damage as much as possible is going on all over the world. Increasing public awareness about earthquakes.

Earthquake felt in different parts of the country including Dhaka Earthquake was felt in different parts of the country including the capital Dhaka. This earthquake was felt on Friday 03 January 2025 at 10:32 am. According to the Met Office, the magnitude of the earthquake was 5 on the Richter scale. However, initially, the amount of damage in the earthquake was not known. Apart from Dhaka, the earthquake was felt in Sylhet.

It is also reported that the earthquake was felt in ComillaRubayet Kabir, officer-in-charge of the Earthquake Monitoring and Research Center of the Meteorological Department, said that the earthquake was felt in different parts of the country including the capital at 10:32 in the morning. Its magnitude was 5 on the Richter scale. This meteorologist said that this earthquake originated from a place in Myanmar. As a result, tremors were felt in Dhaka, Sylhet in the northeastern region and some areas around it. The meteorologist of the Sylhet Meteorological Office, after a long time, an earthquake was felt in Sylhet at 10:32 this morning. It was a magnitude 5 earthquake on the Richter scale. The origin of the earthquake was Myanmar.

Meanwhile, the United States Geological Survey, USGS, said an earthquake was felt in Phek, Nagaland, India at 10:32 a.m. on Friday. According to the USGS, the magnitude of the earthquake was 5 on the Richter scale. Before this, on December 16, 2024, a mild earthquake was felt in the northern part of Bangladesh at 8:10 PM. The magnitude of the earthquake was 4.3 on the Richter scale. However, it is more important to be aware of the earthquake than to panic. Adhering to proper building codes while constructing buildings is important, above all to know what to do to avoid damage in earthquakes. 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—you should know that an earthquake is happening. In simple words, the shaking of the earth is an earthquake. And an 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 increasing by leaps and bounds. But the quality of those structures, whether they will survive a major earthquake or not, is highly feared.

Our big cities also do not have the necessary open spaces 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 be protected from the disaster of earthquake, all kinds of structures should be made suitable for dealing with this disasterAn 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 surface changes, volcanic eruptions, and landslides.

> Earthquake stability

Earthquakes usually last a few seconds. But this can cause massive destruction in a matter of 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 higher 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.

> 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 there is a vibration on the surface of the earth, that is an earthquake.

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

And 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:

> Earthquake risk and Bangladesh context

Among the natural disasters that occur, we have experience of floods, cyclones, floods, floods, etc., but we do not have the bitter knowledge of earthquakes. Incidentally, the United Nations says that Dhaka is one of the 20 most dangerous cities in the world Besides, Bangladesh is the worldDue to its location in an earthquake-prone region, earthquakes occur occasionally in this country since ancient times In addition, the Himalayan range is the most earthquake-prone region in Asia Although fortunately the people of Bangladesh did not have to accept the bitter taste of strong earthquakes, however, a review of the events of the last two centuries shows thatThere is a great fear of earthquakes in the north, north-east region, south-east region of Bangladesh For example, the deadly earthquake that occurred near Shillong in Meghalaya on June 12, 1897 caused many cities in Bangladesh, including Dhaka, Sylhet, and Mymensingh, to collapse and kill many people.

Past 21stA major earthquake hit Chittagong and adjoining areas in November 1997, and in July-August 1999, Maheshkhali and surrounding areas were similarly hit by four earthquakes, resulting in several deaths and destruction of houses. In addition, according to records, 10 times in 1998There were 21 earthquakes in 1999 and 14 earthquakes till April 2000, which clearly indicates that earthquakes can strike Bangladesh at any time. And only in the last year and a half, there have been 19 earthquakes in Bangladesh. Most of the magnitudes were between 4 and 5. According to USGS data, among the recent earthquakes that originated in Bangladesh, the highest magnitude was an earthquake that occurred on July 26, 2003. It is felt in Chittagong and Khagrachari. The magnitude was 5.6.

Bangladesh has experienced three earthquakes of more than magnitude 6 in the last one year. Two were magnitude 5.1 on August 15, 2022. Most magnitudes were between 4 and 5. 10 had their source in Chittagong and Cox's Bazar area.

History shows that earthquakes have changed the course of rivers or created mountains and hills Geologists and historians believe that the change in the course of the Brahmaputra river, the creation of Madhupur, is due to an earthquake. In addition, 19 million people live in an area of only 55 thousand square miles, unplanned urbanization andRisky unauthorized buildings will exacerbate potential earthquake damage In such a situation, it is absolutely necessary to gain proper knowledge about earthquakes and take necessary preparations and be aware

> 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, public awareness should be developed. 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 to the end of the construction of a building, the concerned person or organization should be strictly monitored to see if all the rules are followed or not.

Finally, the government should take proper steps to deal with the earthquake. In particular, provision of machinery to remove concrete piles after major earthquakes, identifying and demolishing or rectification of weak infrastructure in the city, proper adherence to building codes in construction of new buildings, strengthening of RAJUK, eradicating corruption from RAJUK, proper construction of buildings.

Formulating and verifying the design, not building more than four-five floors in places, discouraging cluster housing, not constructing buildings by filling up water bodies, enforcing legal punishment for filling water bodies, restoring city canals, keeping rivers free from pollution and various public-private initiatives. About institutions and individualsFormation of earthquake cell etc.There is no substitute for public awareness to reduce earthquake damage.Earthquake awareness campaign in every ward of Dhaka City Corporation, if earthquake awareness activities are taken in every office, it will enliven the people of the city greatly and people will be more aware about what to do during an earthquake.

The writer is a, columnist and researcher Founder Chairman, jatia rogi kallyan Society Chamber, Alankar Shopping Complex Chittagong.