Earthquakes and Tectonic Landforms

Young folded mountains are located at tectonic plate boundaries where crustal movement is most active, making them the most prone to seismic activity and earthquakes.

An isoseismic line is a line on a map connecting points where an earthquake has the same intensity. Isobars connect points of equal pressure, and isotherms connect points of equal temperature.

An earthquake is defined as the shaking or vibration of the Earth's surface caused by the release of energy from the crust, typically due to tectonic plate movement.

An earthquake is the sudden shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can be violent enough to toss people around and destroy whole cities. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.

The Richter scale is a logarithmic scale, meaning each whole number increase represents a tenfold increase in measured amplitude.

Seismic waves are waves of energy that travel through the Earth's layers, and are a result of an Earthquake or a volcano that imparts low-frequency acoustic energy.

Jaisalmer is located in a relatively stable geological region compared to the highly active seismic zones of the Himalayas (Kangra, Dehra Dun, North Bihar).

Seismic waves that vibrate perpendicular to the direction of travel are S-waves (secondary waves). S-waves are shear waves and cannot travel through liquids, meaning they only travel through the solid parts of the Earth.

The Richter scale was originally devised to measure the magnitude of earthquakes of moderate size (that is, magnitude 3 to magnitude 7) by assigning a number that would allow the size of one earthquake to be compared with another.

A seismograph or seismometer is an instrument which is used to record the direction of movement of earthquake waves. The first seismograph was invented in 132 A.D. by the Chinese astronomer and mathematician Chang Heng.

All three following instruments are useful in measuring the seismic activity under the earth's surface. A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions. Richter scale a quantitative measure of an earthquake's magnitude. The modified Mercalli intensity scale also measures the effect of an earthquake on the Earth's surface. 

The modified Mercalli intensity scale also measures the effect of an earthquake on the Earth's surface. The Mercalli scale grades the earthquake on a 12-point scale. The intensity scale helps to analyze the data by constructing isoseismal curves, which are lines that connect points of equal intensity. 

• There are a number of ways to measure the magnitude of an earthquake. The first widely-used method, the Richter scale, was developed by Charles F. Richter in 1934. It used a formula based on the amplitude of the largest wave recorded on a specific type of seismometer and the distance between the earthquake and the seismometer.
  
• Another way to measure the strength of an earthquake is to use the Mercalli scale. Invented by Giuseppe Mercalli in 1902, this scale uses the observations of the people who experienced the earthquake to estimate its intensity.
  

A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions, and explosions. Seismometers are usually combined with a timing device and a recording device to form a seismograph

True,

Narmada river rises in the Amarkantaka hills in Madhya Pradesh. It flows towards the west in a rift valley formed due to faulting. Its length is about 1312 km. This river drains into the Arabian Sea. It flows through the states of Madhya Pradesh, Maharashtra, and Gujarat.

• A Rift valley is a narrow linear depression in the land surrounded by mountain ranges. It is created by a geological fault in earth's crust. The East African Rift valley which runs thousands of km long is the best example of a Rift valley in the world.

• When two plates of earth's crust move apart from each other, a long narrow depression is formed due to the sinking of ground which is called a rift valley eg. east African rift valley. Hence option C is the right answer.
• The rift valley is not formed due to river or aeolian(wind) action. Also, the slope in the rift valley is almost vertical thus very steep hence other options are incorrect.

A rift valley is a lowland region that forms where Earth's tectonic plates move apart, or rift. This is a direct result of tectonic forces, unlike V-shaped valleys (river erosion) or U-shaped valleys (glacial erosion).

The Damodar River flows through a rift valley in the Chota Nagpur Plateau region. This rift valley was formed due to down-warping of the crust.

The Narmada River flows through a well-known rift valley located between the Vindhya and Satpura ranges in central India.

Lonar Lake (A), Toba Lake (C), and Keloed Lake (D) are all volcanic crater lakes. Bhim Tal is a lake in the Kumaun region, but it is not of volcanic origin.

The Wular lake is integral to the hydrological system of the Kashmir valley. India's largest freshwater lake, the Wular lake was formed as a result of the tectonic activity and is fed by the Jhelum river. The lake, along with its marshes, regulates the water levels and offers protection against flooding.