Learn TNPSC exam and online pratice


Q1. What is Plate Tectonics?
A theory in Geology. Explains the large scale motions of the Earth's crust. It tells us that it is not only the continents that are in motion but the oceans as well.
Q2. What is a Plate?
The top crust of the Earth, is not single shell of granite and basalt, but a mosaic of several rigid segments called Plates.
Q3. What is Astenosphere and what is its function?
The denser mantle below the earth's crust is called so. It carries the continents and oceans on their backs like a mammoth rafts.
Q4. What is the average thickness of the plates?
100 Kms.
Q5. What is the average rate of movements of the Plates?
At the rate of about 20 cms a year.
Q6. What are the types of plates?

1. Constructive    2. Destructive   and   3. Conservative.

Q7. What is a Constructive Plate?
Movement is well illustrated in the Atlantic oceans. At the mid ocean ridge, new ocean floor is continuously being produced, as the Americas move further apart from Europe and Africa.
Q8. What is a Destructive Plate?
Found on all sides of Pacific ocean, on the various plates slide down beneath the surrounding Lithosphere.
Q9. What is a Conservative Plate?
It arises where adjacent plates slide past one another along transform faults. This type of movement can cause the most destructive earthquakes.
Q10. What are "transform faults"?
Are geological fault - planar rock fractures which show evidence of relative movement.
Q11. What are "transform boundaries"?
Occurs where plates slide, or, perhaps more accurately, grind past each other along transform faults.
Q12. What are divergent boundaries?
Occur where two plates slide apart from each other.
Q13. What causes Earthquakes?
The plates cannot simply glide past each other because of friction. Thus, stress builds up in both plates and when the stress exceeds, potential energy is released as strain. The energy thus released results in earthquakes.
Q14. What type of boundaries causes the most earthquakes?
Transform boundaries.
Q15. What causes the most destructive earthquakes?
Conservative plate movements.
Q16. In simple terms, what is an earthquake?
It is the shaking of the ground, caused by the movement of earth's crust, causing land slides, destruction of buildings and so on. Technically, it is the sudden release of energy in the Earth's crust, creating the seismic waves.
Q17. What are Seismic Waves?
A wave of energy that travel through the Earth, most often by an earthquake and sometimes by powerful explosions.
Q18. What is "Hypocenter" or "Focus"?
Earthquake's underground point of origin.
Q19. What is "Epicenter"?
The point of the earthquake on the earth's surface vertically above the underground point.
Q20. What is a fault?
An erroneous crack or break in the rock strata of the earth's crust caused by vertical or horizontal movement.
Q21. What is the study of earthquakes?

Seismology - professionals involved in this are called Seismologists.

Q22. What are the instruments used to measure earthquakes?

Richter Scale - invented by Charles Richter in 1935. Measures the energy released by the earthquakes. Mercalli Scale - a modified version and widely used for the measurement of the intensity of earthquakes.

Q23. What is the highest recordable number in Richter Scale?
Nine - the maximum so far recorded is only 8.9.
Q24. Which is the most deadliest earthquakes ever recorded?
SHAN XI in China in 1556, which killed more than 8 lakh people.
Q25. Which is the deadliest earthquake in the modern days?
28.7.1976 TANG SHAN, China - killing over 2.25 lakh people. (Earlier in May 2008 an earthquake occured in Chichuan province of china, 35000 people).
Q26. What are the recent past earthquakes in India and India-Pakistan borders?

1. 30.9.1993 - Lattur, Maharashtra - 7600 deaths. 26.1.2001 - Bhuj Dt., Maharashtra - 30000 deaths.

2. 08.10.2005 - Jammu and Kashmir NW region 79000 deaths. Most of the deaths have occured in the Pakistan occupied Kashmir.

Q27. What was the major earthquake in 2010?
Q28. What is Tsunami?
It is a Japanese word meaning - TSU-Harbour and NAMI - waves. It is the underwater earthquake in deep oceans because of which high tidal waves occur over the oceans and entering into the coastal regions.
Q29. What was the major recent occurrence of Tsunami?

26.12.2004 - at Sumatra in Indonesia in the Indian Ocean. It affected the coastal region/districts of Tamilnadu like Nagapattinam, Cuddalore,Chennai, Andamans.

Q30. Which are the countries which got affected in the Tsunami on 26.12.2004?
India, Sri Lanka, Indonesia, and Thailand. The casualty of this Tsunami was nearly 2.5 lakh.
Q31. Which province of Thailand was the worst affected in the 2004 Tsunami?
Aceh Province.
Q32. What are the previous occasions of Tsunami?
 1. 1703 - Japan   -- 5233 deaths.
 2. 1707 - Japan   - 30000 deaths.
 3. 1771 - Japan   - 13846 deaths.
 4. 1782 - South China Sea   - 40000 deaths.
 5. 1792 - Japan   - 15030 deaths.
 6. 1826 - Japan   - 27000 deaths.
 7. 1868 - Chile   - 25674 deaths.
 8. 1883 - Krakatoa   - 36000 deaths.
 9. 1896 - Japan   - 22070 deaths.