Submitted to: Dr. M.K. Shrimali Dr. S.D. Bharti Structure Engineering Department MNIT, Jaipur.

1. A SEMINAR REPORT ONRecent Earthquakes in Indian Subcontinent Submitted by: Anurag Sharma Student Mtech Structural Engineering MNIT, Jaipur. Submitted to: Dr. M.K. Shrimali Dr. S.D. Bharti Structure Engineering Department MNIT, Jaipur.

2. AFTER THE BHUJ EARTHQUAKE • 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

3. EARTH AND ITS INTERIORS • Earth cooled down • masses became integrated together • heavier ones going towards the center • lighter ones rising up.

4. Distinct layers of masses • Earth primarily consists of four distinct layers

5. The inner core • The outer core • The mantle • and the crust

7. 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.

8. Flow of hot mantle upwards to the surface of the earth at the ridges due to convective circulation of the earth’s mantle.

9. Major tectonic plates on the earth’s surface (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.)

10. RADIOACTIVITY INSIDE THE EARTH.

11. Types of interplate boundaries (Source: Murty, C.V.R. “IITK-BMPTC Earthquake Tips.” Public domain

12. 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.)

13. SCALES • The U.S. Geological Survey (USGS) is responsible for providing information about earthquakes to other government agencies and to the public.

14. 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

15. 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.

16. NORTH ANDAMAN (DIGLIPUR) EARTHQUAKE OF 14 SEPTEMBER 2002 • 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.

17. 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.

19. 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.

20. PAST SEISMICITY • 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.

22. Region is witnessing a new phase of seismic activity. • Ongoing post-seismic relaxation

23. Shibpur, Aerial Bay Jetty and Kerala estimated to be VII on MSK scale.

24. Many schools, community and residential buildings in • Nabagram • Kalighat • Ramanagar and • Kishorinagar suffered damage.

26. 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.

27. GEOLOGY AND SOIL CONDITIONS OF THE REGION

29. 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.

31. 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.

32. 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.

33. HARBOUR STRUCTURES • Diglipur Harbour (Arial Bay Jetty) The entire approach and berthing structure consists of • 400 mm square reinforced concrete piles connected at the top by a box-type pier cap made of beams, columns, braces and slabs.

36. Mayabunder Harbour • 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;

38. AIRPORT • 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.

39. Sumatra Earthquake and Indian Ocean Tsunami of December 26, 2004 • 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.

40. 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

43. 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.

44. 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.

45. 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.

47. 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

48. Damage to Infrastructure • 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.

50. 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. • .