The document discusses the geological and geomorphologic perspectives of earthquake risk, particularly in Bangladesh, which is vulnerable to seismic activity due to its tectonic positioning. It details historical earthquake events, their potential effects, and emphasizes the need for risk mitigation measures and public awareness regarding earthquake preparedness. The conclusion calls for a comprehensive disaster mitigation plan and the enhancement of building codes to better protect urban and rural areas from future earthquake impacts.

1. Course No: DM 5113
Course Title: Disaster Management: Geological and Geomorphologic Perspectives
Earthquake and Bangladesh
Submitted to:
Prof. Dr. A.S.M. Woobaidullah
Professor
Department of Geology
University of Dhaka
Dept. of Geography and Environment
University of Dhaka

2. Contents
• Overview of Earthquake
• Earthquake in Bangladesh
• Earthquake probability in
Bangladesh
• Causes of earthquake in Bangladesh
• Earthquake risk in Dhaka
• Effects of earthquake in Bangladesh
• Earthquake risk mitigation in
Bangladesh
• Conclusion

3. Overview of Earthquake
• Shaking of the earth caused by the sudden displacement of rock blocks along
plate boundaries and faults.
• Reasons can be natural or human activities. The most common scale used for
measuring an earthquake is Richter Scale.
• Earthquakes have secondary hazards like flood, landslides, fire, Tsunamis,
Liquefaction etc.
•Due to the subduction of the
Philippine Sea plate beneath
the Okinawa plate and
Amurian plate, Japan has
observed a series of several
high-intensity earthquakes.
•Death tolls from major event
sighted as 255,000 at
Tangshan in China 1976.

4. Earthquake in Bangladesh
•By its geographical position, Bangladesh is
being treated as one very vulnerable country
with its high risk of earthquake attack.
• Bangladesh is located in a tectonically active
much of the country including Chittagong,
Sylhet, Dhaka, Rangpur, Bogra, Mymensingh,
Comilla, Rajshahi are very much vulnerable to
major earthquake disaster.
•Bangladesh can be divided into three main
earthquake zones:
•Zone-1: Sylhet-Mymensingh is with the
possible magnitude of 7 on Richter scale.
•Zone-2: Chittagong-Comilla-Dhaka
and Tangail are with the possible
magnitude of 6 on Richter scale.
•Zone-3: Rest of the country is with
possible magnitude of 6 on Richter scale.

5. Earthquake in Bangladesh
Considering geology and tectonics of Bangladesh and neighborhood five tectonic blocks
can be identified which have been active in producing damaging earthquakes. These are-
Bogra fault zone ƒ
Tripura fault zone ƒ
Sub Dauki fault zone ƒ
Shillong fault zone ƒ
Assam fault zone
Table-3. Maximum earthquake magnitude in different tectonic blocks.

6. Earthquake probability in Bangladesh
•More than 100 earthquake vibrated Bangladesh only after the year 1900. Among these more
than 65 earthquakes attacked after the year 1960.
•During the last 150 years, seven major earthquakes (with M >_7) have affected Bangladesh.
•So far at least 12 large-to-great earthquakes occurred in and around Bangladesh.
•Kamal, a professor of geological sciences at Dhaka University, said, "We have faced two or
three severe earthquakes within the last 150 years... But because of the long interval since the
last major tremor, the possibility of a dangerous strike in the near future is rising."
Table. Major earthquakes affecting Bangladesh.

7. According to recently released research from a team of scientists led by Dr.
Michael Steckler from Columbia University, buried under miles of sediment
lies a locked and loaded megathrust fault that could unleash an earthquake up
to 9.0 magnitude in one of the most densely populated regions of the world.
A vast majority of these megathrust faults and their resulting earthquakes
occur under the ocean, which is why they can unleash tsunamis.
The study indicates that more than 140 million people live within 100
kilometers (60 miles) of this fault in Bangladesh, India and Myanmar.
Contd….

9. Causes of earthquake in Bangladesh
•Bangladesh is situated adjacent to the plate
margins of India and Eurasia where
devastating earthquake have occurred in the
past and still now Bangladesh is seismically
active.
•The Dauki fault, the 150 km long
Madhupur fault, the Assam-Sylhet fault,
and the Chittagong-Myanmar plate
boundary fault
•The decreasing tendency of the water
under the land is also being counted as
another main reason for earthquake.
•constructing large dams and buildings,
drilling and injecting liquid into wells, coal
mining and oil drilling.
•many multistoried buildings have been
constructed without proper earthquake
consideration
Figure. Tectonic Fault in Northern Part of Bangladesh.

10. Earthquake risk in Dhaka
Figure. Earthquake hazard zoning map of Dhaka Megacity.
•Geologically active faults within 50 to
500km distance from Dhaka.
•Dhaka is among of the 20 largest world
cities which is in danger risk of
Earthquake.
• some of earthquakes happened in 1762,
1812, 1865, 1865 and 1897.
•If 7-8 grade in Richter scale of
earthquake happen in Dhaka, 70-80% of
concrete structures will just collapse and
about 30,00,000 people will die. (source :
The daily Star)
•Causes behind-
•Sitting on seduction zone.
•Soil characteristics
•Massive building construction
•Disobeying building codes

11. Earthquake risk in Dhaka

12. Effects of earthquake in Bangladesh
Ground rupture
It is the main result of an earthquake strike. Shaking of
ground causes severe damage to the buildings or other
structures on the ground including houses etc. Shaking of
ground at a particular place depends upon the distance of
that place from the epicenter. Severe shaking of ground
causes destruction of all the buildings of a city and many
people die by burring into the building materials.
Soil liquefaction
When severe shaking occur then soil or sand loses their
strength for a temporary period and gets converted from
solid to liquid. This liquefaction causes sinking of
buildings, bridges etc.

13. Effects of earthquake in Bangladesh
Landslides
Earthquakes causes instability of land
results into landslides. This claims many
lives in the effected zone.
Fire
Earthquake causes breaking of electrical
power lines or gas supply lines which
causes incidents of fires. Water lines
also got ruptured and decreased pressure
makes it impossible to control the spread
of fire. In earthquake of San Francisco
in 1906, more deaths happened because
of fire as compared to earthquake itself.

14. Effects of earthquake in Bangladesh
The probable scenario for an earthquake to a scale of M 6.5 or above in Dhaka city
could cause: ƒ
•Panic among the city dwellers and no knowledge of what is to be done during and
immediately after the earthquake occurrence.
ƒ
•Possible sinking of many of the buildings on filled earth with shallow foundations
due to the liquefaction effect. ƒ
• If the earthquake occurs during monsoon time possible damage of the Dhaka flood
protection embankment due to liquefaction effect causing sudden submergence of a
large area. ƒ
•Large scale damage and some collapse of poorly constructed and old buildings.
ƒ
•Possible outbreak of fire in most of the buildings from the gas lines (the residential
ovens are mostly in burning condition from morning to mid-night) ƒ
•Possible damage of power installations and power cut off for indefinite period. ƒ

15. •Water supply failure as almost all the deep tube wells are run by power, and possible
water line damage ƒ
•Damage of roads and blockage of traffic due to falling of debris from collapsed
buildings and other installations on or near roads. ƒ
•Some of the hospital buildings may collapse killing a large number of inmates and
stopping medical facilities for the disaster victims. ƒ
•Some of the school building may collapse killing and injuring a large number of
students ƒ
•An after shock may cause further collapse of many of the already damaged buildings. ƒ
•
•A few rescue equipment whatever is available, can not be operated due to the lack of
guidance, availability of operators, some will be non-functional, some will be under the
rubbles, some can not find access to rescue spots due to road blockage, etc.
Effects of earthquake in Bangladesh

16. Earthquake risk mitigation in Bangladesh
•Make an inventory of all old buildings which are vulnerable to
earthquake
• Make an inventory of houses, which are constructed at the foot
of steep hillsides,
•Make earthquake vulnerability atlas of major cities,
•Strict application of building codes for all newly constructed
buildings, particularly all high-rise buildings. ƒ
•Development of awareness program to educate people regarding
the causes and consequences of earthquakes and also to
disseminate knowledge to them regarding their responsibilities
before, during and after the earthquake through seminar,
symposium and workshop, and also through non-formal education
by GO and NGOs.

17. For earthquake disaster mitigation, the following measures should be given top priority ƒ
•Increase public awareness about earthquakes through mass media, education (at school),
training, earthquake drills, publications etc. ƒ
•Refined assessment of probable ground motion and identifying local soil effects. ƒ
•Reliable assessment of probable damage to buildings and other structures. ƒ
•Survey and identification of risky buildings ƒUpdating of the building code. ƒ
•Legal enforcement of building code. ƒBuilding insurance to promote earthquake resistant
construction. ƒ
•Seismic strengthening of critical structures and facilities. ƒ
•Developing laboratory and testing facilities for research. ƒ
•Developing low-cost seismic strengthening techniques so that individual house owners
are encouraged to adopt them. ƒ
•Training of engineers, planners, architects and construction workers. ƒ
•Automatic safety shutdown system for gas and electricity during a major earthquake ƒ
•Developing facilities for post earthquake rescue and recovery. ƒ
•Urban (including transport) planning of the city to mitigate earthquake effects. ƒ
•Implementation of national earthquake disaster management plan involving various
professionals, officials and volunteers.
Earthquake risk mitigation in Bangladesh

18. What To Do In An Earthquake
• What to Do During an Earthquake
• Stay calm! If you're indoors, stay inside. If you're outside, stay outside.
• If you're indoors, stand against a wall near the center of the building, stand in a
doorway, or crawl under heavy furniture (a desk or table). Stay away from windows
and outside doors.
• If you're outdoors, stay in the open away from power lines or anything that might
fall. Stay away from buildings (stuff might fall off the building or the building
could fall on you).
• Don't use matches, candles, or any flame. Broken gas lines and fire don't mix.
• If you're in a car, stop the car and stay inside the car until the earthquake stops.
• Don't use elevators (they'll probably get stuck anyway).

19. What to Do After an Earthquake
• Check yourself and others for injuries. Provide first aid for anyone who
needs it.
• Check water, gas, and electric lines for damage. If any are damaged, shut off
the valves. Check for the smell of gas. If you smell it, open all the windows
and doors, leave immediately.
• Turn on the radio. Don't use the phone unless it's an emergency.
• Stay out of damaged buildings.
• Be careful of chimneys (they may fall on you).
• Stay away from beaches. Tsunamis and seiches sometimes hit after the
ground has stopped shaking.
• Stay away from damaged areas.
• If we were at school or work, follow the emergency plan or the instructions
of the person in charge.
• Expect aftershocks.

20. CONCLUSIONS
•Earthquakes pose a gigantic threat to the economy and well being of
this country.
•While thousands of buildings may collapse in the cities, serious
casualties could be in tens of thousands.
•Seismic risks should be correctly assessed and subsequently mitigated
to the extent feasible.
• A comprehensive and well-coordinated earthquake disaster
mitigation plan for the urban as well as rural areas should be
developed without further delay and implemented on a priority basis
with available resources.
•Earthquake engineering research centers should be promoted to be
focal points for providing expert technical guidance to the country for
earthquake disaster mitigation.
•Building codes need to be updated and improved.

21. Thank You