True or False: Seismic waves can be used to map the interior of Earth True False
The Correct Answer and Explanation is:
Correct Answer: True
Seismic waves can be used to map the interior of the Earth.
Explanation
Seismic waves, generated by earthquakes or artificial explosions, are vital tools for understanding the structure of Earth’s interior. These waves travel through the Earth and are recorded by instruments called seismometers. Because different materials affect seismic waves in unique ways, scientists can use changes in wave speed and direction to infer the composition, state, and structure of the Earth’s inner layers.
There are two main types of seismic waves: body waves and surface waves. Body waves include P-waves (primary waves) and S-waves (secondary waves). P-waves are compressional and can travel through both solids and liquids, while S-waves are shear waves that only travel through solids.
One of the most important discoveries using seismic waves is that the Earth’s outer core is liquid. This was determined because S-waves do not travel through the outer core, creating a shadow zone on the opposite side of the Earth from where the earthquake occurred. In contrast, P-waves do pass through the outer core, but they slow down and refract (change direction), which also helps map its boundaries.
Seismic wave behavior also helped scientists identify the crust, mantle, outer core, and inner core of the Earth. The Mohorovičić discontinuity (Moho), which separates the crust from the mantle, was discovered when waves suddenly increased in velocity, indicating a change in material density.
Modern techniques like seismic tomography use data from thousands of earthquakes to create 3D images of the Earth’s interior, much like a CT scan in medicine. These images reveal subducting tectonic plates, mantle plumes, and other deep Earth processes.
In summary, seismic waves provide a non-invasive, highly effective method for studying Earth’s internal structure, offering insights that are impossible to gain through direct observation or drilling.
