1. Vadodara Institute of Engineering Kotambi

2. Civil Engineering department Shukla Priyanka 130800106045 Sharma Manish 130800106043 Shelediya Keyur 130800106044 Guided by: Prof. Dharti Soni Topic: Earthquake,Tsunami,Plate tectonics Subject :Geotechnics and Applied Geology Subject Code :(2130606) Vadodara Institute of Engineering Kotambi

3. Content  Earthquake 1.Causes of earthquake 2.seismic zoning 3.Process of earthquake 4.Seismic hazard 5.Tsunami  Plate tectonics (a) Types of plates  Types of plate boundaries 1 Divergent 2 Convergent 3 Transform

4. Earthquake  Momentary shaking of the ground or vibration or oscillations of the ground caused by the slip or by volcanic or magnetic activity or other sudden stress changes in the earth are called Earthquake.

5. Causes of Earthquake An Earthquake is result of a sudden release of energy in the Earth’s crust that creates seismic waves. Earthquake are recorded with a seismometer, also known as seismograph. The moment magnitude of an Earthquake is conventionally reported, with magnititude 3 or lower earthquakes being mostly imperceptible and magnitude 7 causing serious damage over large areas.

6. At the Earth’s surface,earthquakes manifest themselves by shaking and sometimes displacing the ground. When a large earthquake epicentre is located offshore,the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.

7. Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear experiments. An earthquake’s point of initial rupture is called its focus or hypocenter.

8. Tsunami Tsunamis are most often caused when an earthquake causes the seafloor to rise or fall. Earthquakes happen when two tectonics plates collide into each other at a plate boundary. The denser plate is sub ducted under the other plate, which leads to a rise or fall of the seafloor. This movement of the seafloor will cause a rapid vertical displacement of water, and waves of a tsunami would form.

9. As the wave approaches the coastline, it would get higher as the seafloor gets shallower, causing a tsunami to become visible and then grow even higher as the water gets more shallow. The shock waves produced by the earthquake would radiate out and cause other waves to form too. Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water.

10. Tectonic plate earthquakes are associated with the earth's crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position. Waves are formed as the displaced water mass, which acts under the influence of gravity, attempts to regain its equilibrium. When large areas of the sea floor elevate or subside, a tsunami can be created.

11. Seismic Hazard Seismic hazard refers to the study of expected earthquake ground motions at the earth's surface, and its likely effects on existing natural conditions and man-made structures for public safety considerations; the results of such studies are published as seismic hazard maps, which identify the relative motion of different areas on a local, regional or national basis.

12. With hazards thus determined, their risks are assessed and included in such areas as building codes for standard buildings, designing larger buildings and infrastructure projects, land use planning and determining insurance rates.

13. Processes Responsible For Earthquake Seismic Sources 1. Natural Sources 2. Man made sources

14. 1. Natural sources

15. o Tectonic Earthquake: The sudden release of strain energy by rupture of the rock at plate boundary (fault plane) is the primary causes of seismic activity around the world. o Volcanic Earthquake: Shallow volcanic earthquake may result from sudden shifting or movement of magma. o Plutonic Earthquake: they are caused by deep seated changes. o Land Slides: Massive landslides associated with the volcanic activity produce significant ground motion.

17. 2. Man Made sources Control Sources Reservoir induced earthquake Mining Induced Earthquake Cultural Noise

19. About Seismic Zoning Of India  The Geological Survey of India (G. S. I.) first published the seismic zoning map of the country in the year 1935 . Color coded in different shades of the color red, this map shows the four distinct seismic zones of India.  Following are the varied seismic zones of the nation, which are prominently shown in the map.

21. Important of Seismic Zoning  This map helps in planning for a natural disaster like earthquake.  An Indian seismic zoning map assists one in identifying the lowest, moderate as well as highest hazardous or earthquake prone areas in India.  Even such maps are looked into before constructing any high rise building so as to check the level of seismology in any particular area.  This in turn results in saving life in the long run.

22. Theory of Plate Tectonics Plate Tectonics Causes of Plate Tectonics

23. Plate Tectonics

24. What is Plate Tectonics The Earth’s crust and upper mantle are broken into sections called plates Plates move around on top of the mantle like rafts

26. What is the Lithosphere? The crust and part of the upper mantle = lithosphere 100 km thick Less dense than the material below it so it “floats”

27. What is the Asthenosphere? The plastic layer below the lithosphere = asthenosphere The plates of the lithosphere float on the asthenosphere

29. 2 Types of Plates Ocean plates - plates below the oceans Continental plates - plates below the continents

30. Mechanism of Plate Tectonics Thought to be convection of the mantle. Friction at base of the lithosphere transfers energy from the asthenosphere to the lithosphere. Convection may have overturned asthenosphere 4–6 times.

31. Ridge Push and Trench Pull Fig. 2.16

32. Hot-spot Volcanism Fig. 2.18

33. PLATE BOUNDARIES Divergent boundaries  plates move apart Convergent boundaries  plates move together Transform boundaries plates slide past 

34. DIVERGENT BOUNDARIES When two plates move apart and magma surfaces forming NEW crust (usually oceanic) continental rift zones (landmass splits into two or more segments) mid-ocean ridges (sea-floor is elevated)

35. DIVERGENT BOUNDARIES Make new crust Rift valley continent-continent

36. DIVERGENT BOUNDARIES Make new crust: Sea Floor Spreading Youngest rocks form at ridge Older rocks are further from ridge Oldest rocks are located at subduction zones

37. DIVERGENT BOUNDARIES Make new crust: Sea Floor Spreading As magma rises and cools, iron and magnesium minerals align themselves to the Earth’s magnetic field “Magnetic Stripes” are formed The Earth’s magnetic field reverses polarity Magnetic stripes are mirrored on each side of the mid-ocean ridge Every ~20,000 years the polarity of the Earth changes. This is change is reflected in the rocks, whose polarity is fixed once the magma is cooled.

38. Convergent Boundaries Boundaries between two plates that are colliding   There are 3 types…

39. Type 1 Ocean plate colliding with a less dense continental plate Subduction Zone: where the less dense plate slides under the more dense plate VOLCANOES occur at subduction zones

41. Andes Mountains, South America

42. Type 2 Ocean plate colliding with another ocean plate The less dense plate slides under the more dense plate creating a subduction zone called a TRENCH

44. Aleutian Islands, Alaska

45. Type 3 A continental plate colliding with another continental plate Have Collision Zones: a place where folded and thrust faulted mountains form.

48. Transform Fault Boundaries Boundary between two plates that are sliding past each other EARTHQUAKES along faults

50. San Andreas Fault, CA

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