earthquake azra qaseem
TRANSCRIPT
EARTHQUAKE
Azra QaseemStudent of M.Sc.(final year)
Department of Environmental SciencesKamla Nehru Institute of Physical and Social
Sciences, Sultanpur, Uttar Pradesh.
Content• Earthquake• Terminology• Cause of Earthquake• Measuring of Earthquake• Classification of Earthquake• Effect of Earthquake• Prediction of Earthquake• Mitigation• Management of Earthquake• Conclusion
Earthquake• The vibration in Earth crust with sudden release of energy
with displacement of mass due to strain at faults by virtue of gravity is known as earthquake.
• An earthquake is a phenomenon that results from the sudden release of stored energy in the Earth's crust that creates seismic waves. At the Earth's surface, earthquakes may manifest themselves by a shaking or displacement of the ground and sometimes tsunamis, which may lead to loss of life and destruction of property.
• Earthquakes may occur naturally or as a result of human activities. In its most generic sense, the word earthquake is used to describe any seismic event—whether a natural phenomenon or an event caused by humans—that generates seismic waves.
Terminology • Focus: The plane or point of origin of an earth quake below the surface of the earth is
terminal as its hypocenter or focus or point of origin.• Epicenter: The point or place on the surface vertically above the focus of a particular
earthquake is termed as its epicenter.• Seismic wave: The energy release from the focus is travels in the form of elastic
waves at different periodical intervals is known as seismic waves. It is of three different types:
WAVES
P-WAVES S- Waves L- Waves
P-Waves/ Primary waves• These are the high speed seismic wave, which
move in straight line sound wave. The speed of these waves are maximum in solid.
Vp = √ λ+2µ/ρλ and µ= elastic constantρ= density
P-Waves
S- Wave / Secondary waves / Transverse wave
• The nature of these waves resemble with water and light waves. These waves passes at perpendicular from the direction of particles movement.
Vs = √ µ/ρµ= elastic constant ρ= density
S- Wave
L- Waves/Longitudinal waves/ surface waves
• These waves more slowly near the surface layers of earth. In character, these waves are of two types.
CAUSES OF EARTHQUAKENatural-Movement of Tectonic
PlatesVolcanic ActivityCosmic ActivityFracturing and
Faulting(Mega-thrust)
Anthropogenic- Injection & Extraction of fluids Nuclear testing Deep Mining Large dam reservoirs
Boundaries and Movements
Global Distribution of Plate Tectonic
Measuring of Earthquake• There are two different ways to measure the
intensity of earthquake:
Mercalli intensity scale Richter Magnitude Scale
Richter Magnitude Scale
Richter Magnitude Scale
CLASSIFICATION OF EARTHQUAKE AND ITS ENERGY RELEASED
Earthquake classification
Magnitude Range Number of Earthquake per Year
Great ≥8 1Major 7-7.9 18Strong 6-6.9 120
Moderate 5-5.9 800Light 4-4.9 6,200
Minor 3-3.9 49,000Tremors 2-2.9 3,00,000
Magnitude
What Controls the Level of Shaking?
The more energy released, the greater potential for damage, regardless of all other factors (and greater areal extent).
Distance Shaking decays with distance
Local soils and bedrock geologySoil characteristics may amplify the shaking.(seasonal climatic variations can impact this)Complex geology tends to dampen waves
FACTORS EFFECTING THE DESTRUCTIVENESS OF
AN EARTHQUAKE
Building codes and materials
EFFECT OF EARTHQUAKEDamage to human structuresDamages to the towns and
citiesLoss of human lives and
propertyDeformation of ground
surfaceFires LandslideFlash flood Tsunami
EXAMPLE OF EARTHQUAKE IN INDIA
2011 Gangtok, S ikk im Earthquake- 18 September 2011, 6.9 magnitude, killing about 118 people
2009Andman Is lands Earthquake- 10 August 2009, 7.7 magnitude, 26 killed
2004 Indian ocean Earthquake- 26 December 2004, 9.3 magnitude, 283,106 killed
2001 Gujarat Earthquake- 26 January 2001, 7.6 magnitude, 20,000 killed
1993 Maharashtra earthquake- September 30, 1993, 6.4 magnitude, Over 20,000 people were killed,
BHUJ EARTHQUAKE OF 26 JANUARY 2001 IN GUJRAT
Magnitude - 7.6 Death - 19,727Injured - 166,000Left Homeless - 600,000Destroyed House – 348,000Damaged - 844,000The Indian state department estimates that the earthquake affected directly or indirectly 15.9 million people out of a total population of 37.8 millions. More than 20,000 cattle are reported killed.
2004 Indian ocean Earthquake26 December 20049.1–9.3 magnitude280,000 deathsAffected areas -
Indonesia , Sri Lanka, India (mostly in Tamil Nadu), Thailand, Maldives, Somalia
2005 Kashmir Earthquake 8 October 2005, 7.6 magnitude, 100,000 died, 138,000 injured, 3.5 million displaced Areas affected -
Pakistan, India, Afghanistan
2011 JAPAN EARTHQUAKE11 March 2011 , 9.0 magnitude, Duration-6 minutes15,889 deaths,6,152 injured,2,609 people missing
NEPAL EARTH QUAKE 25 APRIL 2015
• Time= 11:56:26 Depth= 8.2 km Magnitude= 7.8Affected Countries=
India, China, Bangladesh
Casualties =8,857 dead in Nepal and 9,018 total death 21,952 injured
Prediction of Earthquakes
New technology introduced regarding predication of earthquake:1 – Thermal Infra Red Satellite Data2 – Analysis of ULF/ VLF Electromagnetic signal (ULF= Ultra Low Frequency / VLF= Very Low Frequency)3 – Change in Magnetic properties of rocks4 – Concentration of Radio Active gases in ground water (Radon) 5 – Change in electrical sensitivity of the earth6 – Advance assessment of anomalous behavior of animals (Snakes, Cats, Dogs, Birds, Fishes, etc. )
Mitigation
You can’t stop an earthquake. But you can lessen the effects of that earthquake: • Making pentagonal houses• If you are indoors, stay there. Get under a table or a
desk. If you don’t have a table to hide under, drop to the floor in a sitting position and cover your head
• Stay away from windows , the glass may shatter and cut you
• Use steel rod in the place of iron rod in building material
MANAGEMENT OF EARTHQUAKE• Risk assessment and analysis of earthquake hazards• Preparation of earthquake vulnerability and risk zones
maps• Prediction of occurrence of earthquakes • Earthquake disaster preparedness exercises • Search and rescue operation exercises• Relief operation after the occurrence of earthquake
disaster• Recovery of disaster- affected people from mental,
economics and social problems• Rehabilitations of displaced peoples, etc.
The earthquake cause more damage and kill people include deformation of ground surface ,damage and destruction of human structure such as buildings rails, roads,bridges,dams,factories,destruction of town and cities,loss of human and animal lives and property,voilent fires,landslides,floods,disturbance in groundwater etc. Thus,we can say that earthquake disaster is very dangerous for all living beings.
CONCLUSION
