The study of earthquake is called?

The velocity of these waves is slower than body waves.
-These waves moves in circular way, speed is 4 km/sec
-Its frequences is very less.
-Most of earth quakes caused due to L-waves more damages.
-P&S waves reach the surface, they are converted into long waves (L).
-Measurements of earth quakes: The study of earth quake is called seismology.
-Instrument used to measure earth quake is intensity & damage is called seismography.
-All the earth quake occuring at same time at different places.
-ISO – Line the connects all the equal intensity earthquake occured at different points scales with measure earthquake.
There are 3 types
1. Richter Scale (magnitude scale): In the Richter Scale units of measurement are referred to as magnitudes.
-This scale is logarithmic.
Thus, each unit increase in magnitude represent 10 times more energy released.
-It magnitude crosses 6th point energy of earthquake is rises.
-Richter scale designed by Charles F.Richter in 1935.
2. Mereachi scale: These measures the effect is… intensity of earthquake.
-It has 12 points I to XIII.
-It measured only at epi centres.
3. MSK Scale ( Medvedev Span uvar Karnic scale)
-It measure the effect & entensity of earthquake
-It has 12 points I to XII.

Types of earthquake basing (depth) – 3 types
1) Shallow/minor/min earthquake
-shallow earthquake is effect will be very less generated from 70 km of earth crust. Number of E.q are.
2) Intermediatory/medium Earthquake
-It is effect will be above 70 km & below 300 km generated in earth.
3) Deep focus/major Earthquake
-It si effect generated below 300 km.

Causes for Earthquake:
Geologists of geographists of California, they studied about Earthquake.
-They explained a theory Elastic Rebound theory. Earthquakes classified causes in 5 types which are responsible.
1) Landslide – pressure entered on the earth by the landslide earthquakes occurs.
2) Depth mining – Digging at very lower side of crust for minimise….. purpose.
3) Nuclear test – Due to sound proposed produced while testing nuclear fussion is used at present for nuclear tests.
4) Volcanic causes
a) scattering of volcanic due to heat of there volcaner liquid earth crust gets created.
b) Flow of volcanic, the rocks on the upper surface of earth gets sinked. Ex: Krakatoa (1883), Fujiyama, Kilimanjaro, Cotopaxis.
5) Faulting (Displacement of Rocks) – Earthquake occurs when movement of earth takes a long a line of fracture (Fault) Ex: San Andreas Fault of California (105 Angeles)- 1994 Earthquake.
6) Plate tectonic – The 6 major & 9 minor plates of the earth crust are moving at different rates.
-The plate boundaries are primarly location of earthquake.
-The Ring of fire, shallow focus earthquakes on the Oceanic Ridges. Oceanic trenches (deep focus earthquakes).

World distribution of earthquakes: Earthquake belts.
1) The circum – pacific belt (covergent plate boundaries). pacific locked belt in surrounding of pacific ocean in between 4 continents. North America, South America, Africa&Australia.
2) Central mountain belt: From Alps (Europe) to Himalayas.
-India, Pakistan, Afghanistan, Iran, Iraq, Italy, France.
-India Earthquake prone area
-Globally, earthquake result in a loss of about 50,000 lives every year.
-Earthquake over 5.5 magnitude on the Richter scale are progressively damaging property & human life
-Massive earthquake generally occur near the junction of two technic plates. Along the Himalayan range when the Indian plate goes below Eurasian plates.
-According to latest seismic zoning map brought out the Bureau of Indian Standard (BIS) over 65% of the country is prone to earthquake of intensity.
-India has been divided into 5 seismic zones according to the maximum intensity of earthquake expected.
-In five zones, first&second zones are including in 1997.
In zoneIV – magnitude more 7 point.
-IV is the most active which comprises of whole on
1) North-East India
2) Northern portitionBH
3) U.K East
4) H.P – Kangra
5) J&K – Srinagar
6) Andaman&Nicobar Islands
7) In G.R – Kuch, Bhuz
In zone III- magnitude between 6-7 points more active. Important place Delhi, Sikkim, other ones B.H, UK, GR, J&K, MR-Lathur
In zone II – mostly part of India in this zone.
-magnitude between 4-6 points.
-Places – North GR, RJ, Penisular plateau north port, Narmada lift area, Western& Eastern ghats some are, kolkata, Chennai, Mumbai

Causes of an Earthquake
Earthquakes are caused by tectonic movements in the Earths crust. The main cause is that when tectonic plates collide, one rides over the other causing Orogeny, Earthquakes and Volcanoes.

-The boundaries between moving plates from the largest fault surfaces on Earth. When they stick, relative motion between the plates leads to increasing stress. This continues until the stress rises and breaks, suddenly allowing sliding over the locked portion of the fault, releasing the stored energy.

-Earthquakes sometimes hit cities and kill hindreds of thousands of people. Most earthquakes happen along the Pacific Ring of Fire but the biggest ones mostly happen in other places.