A SEMINAR REPORT ON
Recent Earthquakes in Indian
Subcontinent
Submitted to:
Submitted by:
Dr. M.K. Shrimali
Dr. S.D. Bharti
Structure Engineering Department
MNIT, Jaipur.
Anurag Sharma
Student
Mtech Structural Engineering
MNIT, Jaipur.
1

NORTH ANDAMAN (DIGLIPUR) EARTHQUAKE OF 14
SEPTEMBER 2002

SUMATRA EARTHQUAKE AND INDIAN OCEAN
TSUNAMI OF DECEMBER 26, 2004

2005 NORTH KASHMIR EARTHQUAKE OF OCTOBER
2005

SIKKIM EARTHQUAKE OF 14 FEBRUARY 2006

2011 SIKKIM EARTHQUAKE
2

Earth cooled down

masses became integrated together

heavier ones going towards the center

lighter ones rising up.
3


Distinct layers of masses
Earth primarily consists of four distinct
layers
4

The inner core

The outer core

The mantle

and the crust
5
6


Cluster of a number of plates of various sizes.
This differential movement of the plates provides
the basis of the foundation of the theory of
tectonic earthquake.
7

Flow of hot mantle upwards to the surface of the
earth at the ridges due to convective circulation of
the earth’s mantle.
8
Major tectonic plates on the earth’s surface (Source: Murty, C.V.R. “IITKBMPTC Earthquake Tips.”Public domain, National Information Centre of
Earthquake Engineering. 2005. http://nicee.org/EQTips.php - accessed April
16, 2009.)
9

RADIOACTIVITY INSIDE THE EARTH.
10
Types of interplate boundaries (Source: Murty, C.V.R.
“IITK-BMPTC Earthquake Tips.” Public domain
11
Types of fault (Source: Murty, C.V.R. “IITK-BMPTC
Earthquake Tips.” Public domain, National Information
Centre of Earthquake Engineering. 2005.
http://nicee.org/EQTips.php - accessed April 16,
2009.)
12

The U.S. Geological Survey (USGS) is responsible for
providing information about earthquakes to other
government agencies and to the public.
13


The ML scale is often called the “Richter scale” by the
press and the public.
The moment magnitude scale (abbreviated as MMS;
denoted as MW) is used by seismologists to measure the
size of earthquakes in terms of the energy released
14

The Medvedev-Sponheuer-Karnik scale, also known as
the MSK or MSK-64, is a macro seismic intensity scale
used to evaluate the severity of ground shaking on the
basis of observed effects in an area of the earthquake
occurrence.
15

On 14 September 2002, at

03:58:31 AM a

ML 6.0 (IMD) Mw 6.5 (USGS)

earthquake struck the Northern Andaman Island
region of the Andaman & Nicobar Islands (Union
Territory) of India.
16


The epicenter 165 km NE from Port Blair,
the administrative head quarters of A&N
Islands sea about 24 km SE of Diglipur
Lcation of the epicenter is 13.013°N
93.147°E (USGS), and the focal depth is 33
km.
17
18


After shocks, the largest of them being M 5.3 on
14 September at 04:44 hours and
M 5.2 on 15 September at 01:29 hours.
19


Most severe seismic zone V of the Indian Seismic
Zone map.
Sandwiched between the Indo-Australian plate on
the western side and the Eurasian plate in the north
and the east.
20
21


Region is witnessing a new phase of seismic
activity.
Ongoing post-seismic relaxation
22

Shibpur, Aerial Bay Jetty and Kerala estimated to be
VII on MSK scale.
23

Many schools,
buildings in
community

Nabagram

Kalighat

Ramanagar and

Kishorinagar suffered damage.
and
residential
24
25




Pounding damage was noted to jetty slabs.
Truss members in the old cargo shed at the jetty and
their connections failed.
Mahatma Gandhi Degree College, developed cracks in
their seismic deficient masonry and RC buildings.
Traditional timber and bamboo structures were not
affected to any noticeable degree on these islands, even
in the areas of stronger shaking.
26
27
28


Often these walls are not tied together to create
the necessary box-action in masonry construction
required for lateral resistance.
No positive connection is provided between the
wall and truss members resting on them.
29
30


The Nabagram Panchayat building, suffered
extensive damage to its ground floor columns near
the side farthest from the stiffer side near the stair
case block. Many of the columns were severely
cracked and damaged near beam-column joints
and at mid heights.
No transverse stirrups (ties) were present over a
length greater than 350 mm for the 200 mm wide
columns.
31



The RC columns were not designed for earthquake
forces and required ductility.
Creating the open first storey
And by the lack of transverse stirrups in that storey
where shear resistance is most needed.
32

Diglipur Harbour (Arial Bay Jetty)
The entire
consists of

approach
and
berthing
structure
400 mm square reinforced concrete piles
connected at the top by a box-type pier cap
made of beams, columns, braces and slabs.
33
34
35

Pounding damage was afflicted to the jetty slab
across at expansion joints, which was later
repaired. Subsequent to the earthquake,
vertical cracks were noticed on the piles
supporting the jetty;
36
37


The flexible airstrip developed on unconsolidated
marshy land developed cracks near the centerline.
The cracks were filled with Grade 80/100 bitumen.
The terminal building under construction did not
experience damage. However, the 1.5 m high
boundary wall of the airport premises fell at many
places.
38


The Mw 9.0 earthquake of December 26, 2004
struck at 06:28:53 am.
The maximum intensity of shaking (on the MSK
scale) was VII; along the mainland Indian coast, it
was V.
39


The Tsunami arrived in the states of Andhra
Pradesh and Tamil Nadu along the southeast coast
of the Indian mainland shortly after 09:00 a.m.
At least two hours later, it arrived in the state of
Kerala along the southwest coast

40
41
42

The total number of Indian fatalities was 10,805,
with over 5,640 persons missing, according to
official statistics (www.ndmindia.nic.in 2005). The
state of Tamil Nadu had the highest number of
fatalities — 8,010 (www.tn.gov.in/tsunami 2005) —
with the district of Nagapattinam alone accounting
for 6,065.
43


The western coast of the Middle Andaman Islands
shows emergence of new shallow coral beaches
near Flat Island, suggesting an uplift of up to 0.3
m.
A mud volcano in the Middle Andaman became
active after the earthquake and gray mud and
colorless gases were emitted; this resulted in the
formation of a sub circular mound of about 70 m in
diameter.
44


Many traditional structures are made of wood, and
they performed well in the earthquake shaking.
However, a number of new, poorly constructed
reinforced concrete (RC) structures suffered severe
damage or even collapse due to shaking. The
tsunami waves caused severe destruction in the
coastal areas of the southern islands.
45
46


Not all buildings are properly designed and built to
ensure ductile response.
This building had experienced column damage due
to inadequate lateral reinforcing ties in the 2002
Mw 6.5 Diglipur earthquake
47


A newly constructed 268 m long RC bridge over
the Austen Strait, connecting the North and Middle
Andaman Islands on the Andamann Trunk Road,
had to be closed to even light vehicles.
Three middle spans of the superstructure were
displaced laterally by about 70 cm and vertically by
about 22 cm and fell off the bearing.
48
49



Jetties at Sagar Dweep and Arial Bay were damaged
due to ground shaking,
The 20 MW Suryachakra power plant in the Bamboo
Flat area of Port Blair was adversely affected by the
tsunami waves, which flooded the entire plant.
.
50
51
 Misalignment
of
turbines
caused disruption of electric
generation, which was only
partly restored after ten days.
52


The Mw 7.6 earthquake on October 8, 2005 struck
at 8:50:38 AM local time (9:20:38 India Standard
Time)
epicenter located at 34.493°N, 73.629°E (USGS),
which lies in the Pakistan-occupied territory of
Kashmir (POK).
53

The epicenter is located at 19 km northeast
from the major neighbouring town of
Muzaffarabad, which is 170 km westnorthwest of Srinagar.
54

The official death toll of 47,700 in
Pakistan
55



This earthquake at a focal depth of 26 km.
Tectonic plate moving northward at a rate of 40
mm/yr giving rise to Himalayan mountain ranges.
Worst affected major towns on the Indian side of
LoC are Tangadhar in Kupwara district and Uri in
Baramulla district.
56


The maximum of VIII at Uri, VII at Baramulla and
Kupwara and V at Srinagar on MSK scale.
Top two high risk seismic zones of IV and V of Indian
seismic code IS:1893 with the expected intensity of IX
or more in the zone V and intensity of VIII in the zone
IV.
57



Major civil engineering projects in the area are
highways, bridges, small dams and micro hydro-electric
projects and a few RC framed buildings.
The housing units are largely low rise brick and stone
masonry load bearing types often in association with
timber.
The diaphragms varying from pitched flexible roofs to
mixed flexible and rigid concrete floors and roofs.
58


Primary lateral resistance against the earthquake forces
is provided by the membrane action of the diaphragms
(floors and roofs) and bearing walls.
In Kashmir traditional timber-brick masonry construction
consists of burnt clay bricks filled in a framework of timber to
create a patchwork of masonry, which is confined in small
panels by the surrounding timber elements.
59


No collapse has been observed for such masonry
even in the areas of higher shaking.
This timber-lacing of masonry, which is locally
referred as
(meaning patch
quilt wall) has excellent earthquake-resistant
features.
Dhajji-dewari

60

The army present in the area was the
first one to respond for rescue and
relief despite being seriously affected
by the earthquake.
61
62



Moderate earthquake (reported as Mw 5.3 by USGS
and as ML 5.7 by IMD) occurred in the state of
Sikkim (India) on February 14 2006 at 06:25:23
a.m. local time.
At 27.35°N 88.35°E, near Ralang (South Sikkim),
with a focal depth of 30 km (www.usgs.gov)
At 27.7°N 88.8°E, near Lachung (North Sikkim),
with a focal depth of 33 km.
63
64

The shaking was also felt in the
North-Eastern states of India and in
the neighbouring countries.
65

Sikkim is located in the seismic zone IV of
Indian seismic zoning map with the
expected maximum intensity of shaking as
VIII on the MSK scale.
66


The entire Himalayan belt is one of the most
seismically active regions in the world.
In
last
110
earthquakes
years,
four
great
(magnitude equal to or greater
than 8.0) have occurred along this subduction zone
causing large scale damage in the surrounding
areas (Bilham 2004).
67



Common practice in Sikkim to build residential
buildings using wood/bamboo.
Until tourism industry got a boost.
Most major old buildings in Sikkim are made of
stone masonry with mud mortar.
68



Except for a very few RC buildings involving major
projects
Analysis and design
generally not carried out.
are
the structural drawings are prepared simply based
on previous experiences of engineers on the basis
of a few thumb-rules
69
70
 Roof
generally consists of GI
sheets
supported
on
wood/bamboo
trusses
which
laterally connect the parallel walls
71


Undressed stones used without proper bonding
between adjacent courses of masonry, and also at
the corners.
The mud mortar used as bonding material in these
buildings further aggravates their lateral strength
capacity.
72
 These
buildings were only
“repaired” and not adequate
retrofitted
against
future
events.
73

Floating columns in upper storeys.

Intermediate soft storey in multistoried buildings.

Poor reinforcement detailing.
74
75
 Tashiling
Secretariat,
State
Legislators’ Hostel, Geological
Survey of India (GSI) building at
Deorali, suffered varying degree
of damages
76
77

The nine-storey masonry infill RC frame hostel
building at
 Sikkim
Manipal
Institute
Medical Sciences (SMIMS)
of
 Tadong, Gangtok suffered damages in walls and
columns.
78

Poor material quality,

Poor connection between perpendicular masonry walls

Resulted in out-of-plane failure of one infill
wall, and severe damages to other infill walls in the
building.
79
80

On National Highway 31A, which connects
Sikkim to the rest of country. In the
Tarkhola Bridge between Melli and Rangpo,
spalling of concrete was observed at the top
of central pier near bearings.
81


An RC pedestrian foot bridge constructed in
1989 near STNM Hospital at Gangtok sustained
minor damage in the form of spalling of cover
concrete in one RC beam
corrosion of reinforcement bars.
82



The 2011 Sikkim also known as the 2011
Himalayan earthquake, was a magnitude 6.9
(Mw)
Kanchenjunga Conservation Area, near the
border of Nepal and the Indian state of Sikkim
At 18:10 IST (12:40 UTC) on Sunday, 18
September
83


The quake came just a few days after an
earthquake of 4.2 magnitude hit Haryana's Sonipat
district, sending tremors in New Delhi.
“Continental Indian and Eurasian Plates” Converge
with one another
84
 STRIKE-SLIP
FAULTING
85

Three aftershocks since the earthquake, occurring
magnitudes of 5.7, 5.1, and
4.6 (Mw) within 30 minutes of the initial
at
earthquake.

Kathmandu experienced two aftershocks that both
had a magnitude of 4.8 Mw.
86



Strengthening of existing buildings.
Increasing the lateral strength in one or both
directions, by reinforcement or by increasing wall
areas or the number of walls and columns.
Giving unity to the structure
87

Avoiding the possibility of brittle
modes
of
failure
by
proper
reinforcement and connection of
resisting members.
88


The main purpose of repairs is to bring back
the architectural shape of the building so that
all services start working and the functioning
of building is resumed quickly.
Repair does not pretend to improve the
structural strength of the building and can be
very deceptive for meeting the strength
requirements of the next earthquake.
89

Shotcrete

Epoxy resins

Epoxy mortar

Gypsum cement mortar

Quick-setting cement mortar
90
91
92

Strengthening existing walls

External binding

Strengthening RC members

Strengthening of foundations
93



National information centre for earthquake
engineering.
Wikipedia.
http://web.archive.org/web/2006100905310
6/http://www.asianews.it/view.php?l=en&art
94



http://news.ifeng.com/mainland/detail_2011_09/1
9/9294991_0.shtml.
Sikkim quake: ITBP buildings collapse, Pegong area
badly hit, The Economic Times, 18 September 2011
"The
Times
of
India.Sp.m.timesofindia.com.
http://sp.m.timesofindia.com/PDATOI/articleshow
/10071212.cms. Retrieved 22 September 201
95
◦ Nalbant, S., Steacy, S., Sieh, K., Natawidjaja, D.,
and McCloskey, J. "Seismology: Earthquake risk
on the Sunda trench." Nature. Vol. 435, No. 7043,
756–757. June 9, 2005. Accessed 2009-05-16.
Archived 2011-11-18.
◦ Jayasuriya, Sisira and Peter McCawley, "The Asian
Tsunami: Aid and Reconstruction after a
Disaster". Cheltenham UK and
96
THANKS
A LOT
97