Earthquake in Bangladesh

1. Presented by
Md. Shahadat Hossain Biplab
Md. Nazim Uddin
S.M. Muhibullah

2.  As we all know, the Indian
subcontinent is situated on the Indian
plate. And it has countries like
Bangladesh, India, Pakistan, Nepal,
Bhutan, Maldives, and Sri Lanka.
 The India plate is surrounded by the
Eurasian plate in the north, the
Arabian and Somali plate in the west
and south-west, the Australia plate in
the south and the Burmese plate in the
east.
 Due to the continuous movement of all
plates around the Indian plate and the
Indian plate itself, the Indian plate is
the seismically active zone and has
been facing many major earthquakes
since past centuries. Fig: The Indian Plate (Source: Alataristarion)

3.  Bangladesh is being treated as one very
vulnerable country with its high risk of
earthquake attack by its geographical
position.
 Bangladesh is located in a tectonically
active area and very much vulnerable to
major earthquakes.
 Bangladesh can be divided into three major
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 with possible
magnitude of 6 on Richter Scale. Figure 1 Seismic Zoning Map in BNBC-1993 The
zone coefficient (Z) represents the peak ground
acceleration (PGA) in units of g (acceleration due
to gravity).

4. Considering geology and tectonics of Bangladesh and
neighboring five tectonic blocks can be identified which have
been active in producing damaging earthquakes. They are-
- Bogra Fault Zone
- Tripura Fault Zone
- Sub Dauki Fault Zone
- Shillong Fault Zone
- Assam Fault Zone

5.  More than 100 earthquakes vibrated Bangladesh only after the
year 1900. Among these more than 65 attacked after 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.
 Hence the possibility of a dangerous strike in the near future is
rising.

6. Mega Thrust Covering Bangladesh

7.  Bangladesh is situated adjacent to the plate margins of India
and Eurasia where devastating earthquakes have occurred in
the past and still 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
 Constructing large dams and building, drillings and mining.

8.  Geologically active faults within 50 to 500 km distance from
Dhaka
 Dhaka is among of the 20 largest world cities which is in risk of
Earthquake.
 Some of earthquakes happened in 1762, 1812, 1865, 1897
 If 7-8 grade in Richter scale of earthquake happen in Dhaka,
70-80% of concrete structure will just collapse and about 3
million people will die (Daily Star).

9. Daily Star

10. After 2001 Gujrat earthquake, also known as Bhuj
earthquake in India some prominent earthquakes are,
 NORTH ANDAMAN (DIGLIPUR) EARTHQUAKE OF 14
SEPTEMBER 2002 (Mw=6.5).
 SUMATRA EARTHQUAKE AND INDIAN OCEAN TSUNAMI
OF DECEMBER 26, 2004 (Mw=9.0).
 2005 NORTH KASHMIR EARTHQUAKE OF OCTOBER 2005
(Mw=7.6).
 SIKKIM EARTHQUAKE OF 14 FEBRUARY 2006 (Mw=5.3).
 2011 SIKKIM EARTHQUAKE (Mw=6.9).

11.  The after effect of Sumatra caused, the Tsunami arrival in
the states of Andhra Pradesh and Tamil Nadu along the
southeast coast of the Indian mainland.
 At least two hours later, it arrived in the state of Kerala
along the southwest coast.
 The total number of Indian fatalities was 10,805, with over
5,640 persons missing, according to official statistics
(www.ndmindia.nic.in 2005).
 As a consequence of the Kashmir earthquake (Mw=7.6), the
official death toll was 86,000-87,351 in Pakistan.

12.  Indian subcontinent has suffered some of the greatest
earthquakes in the world with magnitude exceeding 8.0.
 For instance, in a short span of about 50 years, four such
earthquakes occurred:
1. Assam earthquake of 1897 (magnitude 8.7) (Oldham,
1899),
2. Kangra earthquake of 1905 (magnitude 8.6) (Middlemiss,
1910),
3. Bihar-Nepal earthquake of 1934 (magnitude 8.4) (GSI,
1939), and
4. the Assam-Tibet earthquake of 1950 (magnitude 8.7)
(CBG, 1953).

13.  JABALPUR EARTHQUAKE OF 1997 is an another
earthquake with moderate magnitude (Mw=6.0).
 This earthquake is the first moderate earthquake to
have occurred close to a major Indian city in recent
times.
 It provided some indication of what type of seismic
performance to expect out of modern Indian
constructions.
 The maximum intensity was upto VIII (in a very small
area); most parts of Jabalpur town experienced shaking
intensity of VI and VII.

14.  The April 2015 Nepal earthquake (also known as the Gorkha
earthquake).
 It occurred at 11:56 Nepal Standard Time on 25 April 2015,
with a magnitude of 7.8 Mw.
 It killed nearly 9,000 people and injured nearly 22,000 with a
total damage of 10 billion dollars.
 It was the worst natural disaster to strike Nepal since the 1934
Nepal–Bihar earthquake.

15.  Two deadliest earthquake attacked in Pakistan in the previous
time.
 The Azad Kashmir earthquake of 2005 and the Ali Jaan
earthquake in 1935.
 The second one cost the lives of 30,000-60,000 of people and the
first one cost much more as we mentioned before.

16.  Ground Rupture, Soil Liquefaction, Landslides, Fire,
Infrastructures collapse, Sinking, Water supply failure,
blockage of traffice etc. could be caused.
 Panic among the city dwellers and no knowledge of what is to
be done during and immediately after the occurrence.
 If the earthquake occurs in monsoon time possible damage of
the flood protection embankment due to liquefaction effect
causing sudden submergence of large area.
 Possible damage of power installations and power cut off for
indefinite period.

17.  Increase public awareness
 Refined assessment of probable ground motion and identifying
local soil effects
 Relievable assessment of probable damage to buildings and
other structures.
 Survey and identification of risky buildings.
 Updating building codes and legal enforcement
 Developing post-earthquake rescue and recovery
 Urban planning of the city to mitigate earthquake effects
 Implementation of national earthquake management plan

18.  Earthquake pose a gigantic threat to the economy and well
being of a country
 While thousands of buildings may collapse in the cities, serious
casualties could be in tens of thousands
 Seismic risk should be correctly assessed and subsequently
mitigated to the extent feasible
 A comprehensive and well-coordinated earthquake mitigation
plan for the urban as well as rural areas should be developed
 Building codes need to be updated and improved.