Which of the following statements with reference to Richter scale is/are correct ? 1. It is the intensity scale of an earthquake. 2. Richter indicates the amount of energy released during the earthquake. Select the answer using the code given below :
- A.1 only
- B.2 only
- C.Both 1 and 2
- D.Neither 1 nor 2
Correct answer
Explanation
The correct answer is B, 2 only. The Richter scale measures the magnitude of an earthquake, which reflects the energy released at its source, not its intensity.
Charles F. Richter devised the scale in 1935. It is logarithmic: each whole number step means about ten times larger ground motion and roughly 32 times more energy released. Intensity is a different idea. It describes how strongly shaking is felt and how much damage it does at a given place, and it is measured on the Modified Mercalli scale, which runs from I to XII using Roman numerals. One earthquake has one magnitude but many intensities, falling with distance from the epicentre.
A is wrong because statement 1 calls Richter an intensity scale, which it is not. C is wrong because it accepts statement 1. D is wrong because statement 2 is correct.
Exam tip: Richter (and moment magnitude) = energy at the source; Mercalli = intensity of shaking at a place.
Practice Questions
View allWhich one of the following is not a minor plate ?
- A.Cocos Plate
- B.Nazca Plate
- C.Caroline Plate
- D.Antarctic Plate
Show answer
The Antarctic Plate, carrying Antarctica and the ocean around it, is one of the seven major lithospheric plates. Plate tectonics divides the lithosphere into seven major plates and several minor ones.
Read the full explanation →Which of the following statements with reference to shadow zones in an event of an earthquake is/are correct ? 1. Zone between 105° and 145° from epicentre was identified as the shadow zone for both P-waves and S-waves 2. The shadow zone of P-waves is much larger than that of the S-waves Select the answer using the code given below:
- A.1 only
- B.2 only
- C.Both 1 and 2
- D.Neither 1 nor 2
Show answer
The band between 105° and 145° from the epicentre receives neither P-waves nor S-waves, but it is the S-wave shadow zone that is much larger, so statement 2 is wrong.
Read the full explanation →Which of the following statements about Ring of Fire is/are correct ? 1. It is a zone of convergence plate boundaries 2. It is an active seismic and volcanic zone 3. It is associated with deep trench Select the correct answer using the code given below :
- A.1 and 2 only
- B.2 and 3 only
- C.1 only
- D.1, 2 and 3
Show answer
The Ring of Fire around the Pacific is a belt of convergent plate boundaries, full of active volcanoes and earthquakes and lined by deep ocean trenches.
Read the full explanation →Which one of the following rivers is not a tributary of river Brahmaputra ?
- A.River Manas
- B.River Kameng
- C.River Mahananda
- D.River Subansiri
Show answer
The Mahananda rises in the Darjeeling hills, flows through north Bengal and Bihar and joins the Ganga, not the Brahmaputra.
Read the full explanation →Which of the following statements regarding tropical cyclones is/are correct ? 1. These storms develop during the summer and autumn in every tropical ocean except the South Atlantic and eastern South Pacific Oceans. 2. Tropical cyclones that occur in the North Atlantic and eastern North Pacific Oceans are known as typhoons. 3. Tropical cyclones that occur in the Indian and South Pacific Oceans are called cyclones. Select the answer using the code given below :
- A.3 only
- B.1 and 2 only
- C.1 and 3 only
- D.1, 2 and 3
Show answer
Tropical cyclones of the North Atlantic and eastern North Pacific are called hurricanes, not typhoons, so statement 2 is wrong.
Read the full explanation →