Question

Disturbances inside Earth’s core cause earthquakes. The starting point of the disturbance is called the epicenter. Why does the amplitude of a seismic wave usually decrease as the wave moves away from the epicenter?
The waves lose energy in the form of heat.
The frequency of the waves continues to increase.
The wavelength of the waves continues to decrease.
The waves encounter entirely different mediums.

Answer 1

Answer:

The waves lose energy in the form of heat.

Explanation:

The waves of the earthquake loose power and energy due to an exchange in energy, friction between the mediums cause the earthquake to loose energy in form of heat, that makes the earthquake to be much more weak when the waves are traveling far than in the epicenter.

Answer 2

The answer is; The waves encounter entirely different mediums

The amplitude is higher in highly elastic medium (rock) while the amplitude is lower is lessens elastic medium/rock. When the seismic waves meet a denser  medium the amplitude decreases (and the frequency increases). This effect resembles the refraction of light waves. The energy of the wave dissipates as it spreads over a large and larger area from the epicenter.