The Earthquake

Total Questions: 16

1. Based on following statements choose the correct option: [Chhattisgarh P.C.S. (Pre) 2021]

Statement I: Theory of Plate tectonics was given by H.H. Hess in 1967

Statement II: Theory of Plate Tectonics is based on Theory of Sea floor Spreading

(a) Statement -I and Statement - II both are true
(b) Statement I and Statement- II both are false
(c) Statement I is true but Statement - II is false
(d) Statement I is false but Statement - II is true

Correct Answer: (d) Statement I is false but Statement - II is true

Solution:The concept of plate tectonics was formulated during the late 1960s. Wilson, Morgan, Parker, Mckenzie, Harry Hess etc. contributed to the development of this theory. The theory of plate tectonics is based on the ocean (sea) floor spreading theory. Plate Boundaries mainly consist of three types (the fourth is a mixed type), formed in the manner the plates shift in relative to each other. These are collectively referred to as surface phenomena of different types. Plate boundaries are of different types, namely:

Transform boundaries:

These boundaries happen where two lithospheric plates move apart, or maybe further precisely, collide away from one other despite the transform faults, where plates are neither created nor destroyed.

Divergent boundaries:

These boundaries happen when both plates move apart from one another.

Convergent boundaries:

These boundaries happen when both plates move towards one other to form a zone of subduction or a continental collision.

Transform boundaries:

These boundaries happen when natural or human-made structures that cross a transform boundary are offset-split into pieces and carried in opposite directions.

Plate boundary zones:

These boundaries happen where the effects of the interactions are unclear, and the boundaries usually occur along a broad belt.

2. During an earthquake, which type of waves get generated? [Chhattisgarh P.C.S (Pre) 2013]

(a) B.S.L.
(b) A.B.L.
(c) R.S.L.
(d) P.S.L.
(e) F.S.L.

Correct Answer: (d) P.S.L.

Solution:The seismic waves are generated in three forms. (1) P- (Primary) Waves these waves travel fastest. (2) S - (Secondary) Waves- these waves cause particles to oscillate. Both P and S waves are called 'Body waves' because they can travel through the interior of the Earth. (3) Surface Waves - these waves arrive after P and S waves, are confined to surface of the Earth during an earthquake. There are two types of surface wave (1) Love waves and (2) Rayleigh waves.

3. Read the following statement related to 'Earthquake shadow zone' and choose the correct option: [Chhattisgarh P.C.S. (Pre) 2020]

Statement I : The shadow zone of one earthquake is totally different from the shadow zone of another earthquake

Statement II: Seismocmeters record both 'P' and 'S' waves at any distance out of 105° from earthquake's epicentre

(a) Statement I and Statement II both are true
(b) Statement I is true, but Statement II is false
(c) Statement I is false, but Statement II is true
(d) Statement I and Statement II both are false

Correct Answer: (b) Statement I is true, but Statement II is false

Solution:Earthquake waves get recorded is seismographs. However, there exist some specific areas where the waves are not reported. Such a zone is called the 'Shadowzone'. The study of different events reveals that for each earthquake, there exists an altogether different shadow zone. P waves don't arrive between 105° (103°-105°) and 140° due to refraction at the mante-core boundary, however S waves don't reapear beyond an angular distance of~ 130° as they are stopped by the liquid outer core.

4. The 'Ring of Fire' is associated with [U.P.P.C.S. (Pre) 2008]

1. Earthquake

2. Volcanoes

3. Pacific Ocean

4. Forest Fires

Choose your answer with the help of codes given below:

Code:

(a) 1, 2 and 3
(b) 2 and 3
(c) 2 and 4
(d) 1, 2, 3 and 4

Correct Answer: (a) 1, 2 and 3

Solution:'Rings of fire' is a region in the Pacific Ocean influenced by volcanic activities and Earthquake. Approximately 90% of the world's earthquakes occur along the 'Ring of fire'.

The region of 'Rings of fire' includes the vast seismic zone of Chile, California, Alaska, Japan, Philippines, New Zealand etc. The Ring of Fire is stretched to approximately 40,000 kilometers (24,900 miles) tracing boundaries between several tectonic plates including the Pacific, Juan de Fuca, Cocos, Indian-Australian, Nazca, North American, and Philippine Plates. The chain runs up along the western coast of South and North America, crosses over the Aleutian Islands in Alaska, runs down the eastern coast of Asia past New Zealand and into the northern coast of Antarctica. Bolivia, Chile, Ecuador, Peru, Costa Rica, Guatemala, Mexico, United States, Canada, Russia, Japan, Philippines, Australia, Papua New Guinea, Indonesia, New Zealand, and Antarctica are some of the important places located in the ring of the fire.

5. Consider the following statements: [I.A.S. (Pre) 2006]

1. The Richter scale is a logarithmic scale and so an increase of 1 magnitude unit represents a factor of 10 in amplitude.

2. Each integer reading of the Richter scale has an energy 100 times than the previous integer reading.

Which of the statement(s) given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 or 2

Correct Answer: (a) 1 only

Solution:The magnitude of the earthquake is measured on the Richter scale and intensity on Mercalli scale. In 1935, seismologist Charles Francis Richter of the California Institute of Technology developed the Richter magnitude scale. It is based on a logarithmic whose base is 10 on the scale. Each number of seismogram represents 10 times amplitude, 32 times energy release. A seismic wave of magnitude 1 releases the energy of 6 ounces of TNT. Hence statement (1) is correct while statement (2) is wrong.

6. Which of the following instruments is used to record seismic waves? [U.P. P.C.S. (Mains) 2017]

(a) Seismogram
(b) Seismograph
(c) Seismoscope
(d) Seismometer

Correct Answer: (b) Seismograph

Solution:A seismograph is an instrument used to detect and record earthquakes. The seismometer is the internal part of the seismograph, which may be a pendulum or a weight mounted on a spring. However, it is also commonly used as a synonym for seismograph. A seismogram is a recording of an earthquake at a specific location on a seismograph instrument. Hence seismograph usually refers to the seismometer and its recording device as a single unit.

7. Tsunami word belongs to which of the following languages? [Uttarakhand P.C.S. (Pre) 2005]

(a) Arabic
(b) Japanese
(c) Hebrew
(d) Latin

Correct Answer: (b) Japanese

Solution:Tsunami is a Japanese word "tsu" which means 'Harbor' and "nami" means 'wave'. Thus Tsunami means 'harbor wave' arising as a result of the earthquake. These ruptured high waves may cause substantial damage to coastal areas. A tsunami is a series of massive waves produced by an underwater disturbance typically linked to earthquakes that happen beneath or close to the ocean. The Japanese words "tsu" (which means harbour) and "nami" (which means wave) make up the word "tsunami". Unlike normal waves, which are caused by the wind and have short wavelengths, tsunamis are caused by geological events, such as earthquakes, underwater volcanic eruptions, landslides, or even asteroid impacts. They have extremely long wavelengths and can travel at high speeds across ocean basins. With waves arriving every 5 to 60 minutes, tsunamis can attack the shoreline and be dangerous for hours. Tsunami waves frequently resemble walls of water. Tsunamis can occur at any time of day or night.... Read more at: https://vajiramandravi.com/upsc-exam/tsunami/

8. Which one of the following statements about the 2004 Indian Ocean earthquake and the resulting Tsunami is not correct? [47th B.P.S.C. (Pre) 2005]

(a) The earthquake originated due to slipping of about 0115(1,200 km of fault line by 15 m along the subduction zone where the India Plate subducts the Burma plate at the Sunda Trench.
(b) The resulting tsunami devastated the shores ranging from the coast of Indonesia to the east coast of Africa, some 8,500 km away from the epicentre.
(c) As per the current estimates, the quake-generated tsunami killed more than 50 lakh people, in addition to unaccounted dead bodies swept out to sea.
(d) Bangladesh had very few casualties because the quake-affected fault line was in a nearly north-south orientation, the greatest strength of the tsunami waves was in an east-west direction.

Correct Answer: (c) As per the current estimates, the quake-generated tsunami killed more than 50 lakh people, in addition to unaccounted dead bodies swept out to sea.

Solution:Under sea earthquake in the Indian Ocean on 26 December, 2004 produced a tsunami that caused huge natural disaster and over 2 lakh people lost their lives. The earthquake took place in the Indian Ocean off the western coast of Sumatra island of Indonesia. In regards to the options the details of Tsunami is as follows:

Statement (a) - An estimated 1300 Km. of faultline slipped about 15 metre. The earthquake occurred on the interface of the India and Burma tectonic plates. Thus statement (a) is almost right.

Statement (b) The waves devasted on the shores of Indonesia, Sri Lanka, India as far as Somalia on the east coast of Africa. Hence This statement is also nearly true.

Statement (c)-Approx 2-3 Lakhs people were estimated to have lost their lives. Thus statement (c) is wrong. Statement (d) - Bangladesh, which lies at the northern end of the Bay of Bengal had very few casualties. So, statement (d) is true.

9. Which city of Japan had faced tsunami and nuclear radiation recently? [Uttarakhand P.C.S. (Pre) 2010]

(a) Hiroshima
(b) Tokyo
(c) Fukushima
(d) Kobe

Correct Answer: (c) Fukushima

Solution:A major earthquake on 11th March, 2011 with a magnitude (Mw) of 9.0 in Fukushima causes large damage in Japan. Due to this disaster, nuclear power plants were damaged which finally resulted in nuclear radiation.

10. The North-Western Region of the Indian Sub-continent is susceptible to earthquake activity because of- [U.P.P.C.S. (Mains) 2005]

(a) Volcanic activity
(b) plate tectonic activity
(c) coral formation activity
(d) All of the above

Correct Answer: (b) plate tectonic activity

Solution:North-Western region of Indian Subcontinent is susceptible to earthquake activities because it is situated at the border of plates. This area is convergence region of Indian Plate and Eurasian Plate. Coral formation activities and volcanic activities do not occur here.

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