What is Earthquake 678 Wsp

7/31/2019 What is Earthquake 678 Wsp

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What is Earthquake? An Earthquake is a sudden, rapidshaking of the earth caused by thebreaking and shifting of rocksbeneath the earth surface.Over time, stresses build beneaththe Earths surface.Occasionally, stress is releasedresulting in the sudden, and

sometime disastrous shaking we callan earthquake.

The shaking could last seconds or minutes, and there may be severalearthquakes over a period rangingfrom hours to weeks calledforeshocks and after shocks, thelater decreasing in magnitude withtime.


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The Earth


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What Causes Earthquake :The sudden slip at thefault causes theearthquake .a violentshaking of the Earth whenlarge elastic strain energyreleased spreads outthrough seismic wavesthat travel through thebody and along thesurface of the Earth.


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WHAT IS A FAULT? Earthquakes occur on faults. A

fault is a thin zone of crushed rock

between two blocks of rock, andcan be any length, fromcentimeters to thousands of kilometers. When an earthquakeoccurs on one of these faults, therock on one side of the fault slipswith respect to the other. The faultsurface can be vertical, horizontal,or at some angle to the surface of the earth. The slip direction canalso be at any angle. We classify

these into two basic cases: strike-slip and dip-slip motion.


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MAGNITUDE When scientists refer to a

"great" earthquake, they do not meanthe earthquake was fabulous, theymean it was huge. Informally,earthquakes are classified according totheir magnitude size:

under 5 small 5 - 6 moderate 6 - 7 large

7 - 7.8 major 7.8 or above great Intensity Intensity is a qualitative measure of the

actual shaking at a location during anearthquake, and is assigned as Roman

Capital Numerals . There are manyintensity scales. Two commonly usedones are the Modified Mercalli Intensity (MMI) Scale and the MSK Scale . Both scales are quite similar andrange from I- (least perceptive) to XII-

(most severe). The intensity scales arebased on three features of shaking. perception by people and animals, performance of buildings, and changes to natural surroundings.

Basic Difference: Magnitudeversus Intensity

Magnitude of an earthquake is ameasure of its size. For instance,one can measure the size of anEarthquake by the amount of strain

energy released by the fault rupture.This means that the magnitude of theearthquake is a single value for agiven earthquake. On the other hand, intensity is an indicator of theseverity of shaking generated at agiven location. Clearly, the severityof shaking is much higher near theepicenter than farther away. Thus,

during the same earthquake of acertain magnitude, different locationsexperience different levels of intensity.


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Seismic Waves

Large strain energy released during an earthquake travels asseismic waves in all directions through the Earths layers, reflectingand refracting at each interface. These waves are of two types -body waves and surface waves ; the latter are restricted to near theEarths surface Body waves consist of Primary Waves (P-waves)

and Secondary Waves (S-waves) , and surface waves consist of Love waves and Rayleigh waves .

How the Ground Shakes?


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Focal Pont: The point on the fault where slip starts is the Focus or Hypocenter ,

and the point vertically above this on the surface of the Earth is theEpicenter . The depth of focus from the epicenter, called as Focal Depth , is an important parameter in determining the damagingpotential of an earthquake. Most of the damaging earthquakes haveshallow focus with focal depths less than about 70km. Distance fromepicenter to any point of interest is called epicentral distance .


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How Building Twist during the Earthquake?


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Hazard Vulnerability in Gujarat100% of land vulnerable to Earthquakes

11 % of Land liable to severe earthquake( Intensity MSK VI-IXmore)- Kachchh Area

9 % of Land liable to severe earthquake( Intensity MSK V-VIII )Banaskantha, jam nagar, Surendranagar

79.2 % of Land liable to severe earthquake( Intensity MSK III-VI)


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Vulnerability to Earthquake -Gujarat

V

III

IV

II

RANN OF KACHCHH

BHUJ

VAV

RAPAR

UNA

ABDASA

SAMI

DANG

LAKHPAT

DEESA

DASADA

ANJAR

BHACHAU

MULI

MANDVI

KADI

LIMBDI

JASDAN

IDAR

DHARI

THARAD

MORVIJODIYA

HALVAD

SAYLA

MAHUVA

NAKHATRANA

LALPUR

SAVLI

RAJKOT

VAGRA

KALAVAD

DANTA

GONDAL

DHANDHUKA

TALALA

TALAJA

KALYANPUR

JAMNAGARCHOTILA

MUNDRA

VYARA

BAVLA

RAJPIPLABABRA

DHOLKA

MUD

SONGADH

SIHORLATHI AMRELI

PATAN

BOTADJAMBUSAR

MALIYA

UPLETA

SANTALPUR

BHAVNAGAR

KHAMBHALIA

KAPRADA

SANAND

BHILODA

WANKANER

JHALOD

KANKREJ

VALIA

BAYAD

GADHADA

VADIAJETPUR

MALIA

GODHRA

DHRANGADHRA

DEDIAPADA

OLPAD

DAHOD

RAJULA

DHANERA

THASRA

VIRAMGAM

DABHOI

LILIA

JAMJODHPUR

LAKHTAR

JHAGADIA

DHROLHALOL

SAVARKUNDLAVISAVADAR

MAHESANA

PALITANA

BHANVAD

KALOL

KAVANTPADRA

CHIKHLI

PALANPUR

KARJAN

CHUDA

BANSDA

MODASA

WADHWAN

AMOD

KHAMBHAT

KHEDBRAHMA

PARDI

DEHGAM

HARIJ

TANKARA

NIZAR

VADGAM

KESHOD

DEODAR

VALSAD

VIJAPUR

SANKHEDA

TALOD

DASKROI SHEHERA

BHARUCH

AMIRGADH

JETPUR PAVI

ANAND

JUNAGADH

LIMKHEDA

RANAVAV

KHAMBHA

NASVADI

VADODARA

KUTIYANA

MANDAL

KODINAR

HIMATNAGAR

MANGROL

DHARAMPUR

PADDHARI

DHORAJI

MATAR

RANPUR

MEGHRAJ

PORBANDAR

NADIAD

KAPADVANJ

VAGHODIA

BHESAN

UCHCHHAL

LUNAWADA

DHANPUR

BARWALA

BORSADOHKAMANDAL

UMRALA

KADANA

MANSAPRANTIJ

UNJHA

KAMREJ

MANAVADAR

VADALI

VISNAGAR

BHABHERVIJAYNAGAR

VALLABHIPUR

MALPUR

KHEDA

BARDOLI

GHOGHASAGBARA

CHHOTA UDAIPUR

JALALPORE

LODHIKA

SIDHPUR

HANSOT

GARIADHAR

CHANASMA

SANTRAMPUR

KATHLAL

DEVGAD BARIA

JAMKANDORNA

ANKLESVAR

DANTIWADA

UMARPADA

BECHARAJI

VIRPAR

KHERALU

JAFRABADGANDEVI

MENDARDA

CHORASI

BAGASARA

FATEPURA

UMBERGAON

MEHMEDABAD

MUL BANK

ANKLAV

PATAN VERAVAL

TILAKWADA

AHMADABADGANDHIDHAM

PART OF KOTDA SANG

PART OF SANTALPUR

PART OF THE DANGS

PART OF RADHANPUR

PART OF VAV

PART OF BHACHAU

PART OF PADDHARI

PART OF KAPRADA

Earthquake ZoneIIIIIIVV

Taluka Boundary

EARTHQUAKE ZONE AREA - GUJARAT STATE

External Boundaries are not authenticated.Data source : RESECO,Gandhinagar Prep By : GSDMA Ga ndhinagar


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What is Earthquake 678 Wsp