Explain plate tectonics and how it drives natural hazards?

• A. Radiometric decay in the mantle; stable plates cause volcanoes.
• B. Convective movement in the asthenosphere causing plate motion; interactions cause earthquakes, volcanoes, tsunamis.
• C. Magnetic field fluctuations causing crustal cracking; no hazards.
• D. Solar energy heating the crust causing expansion; hazards none.

Answer: (B)

Plate tectonics works because the lithosphere sits on a partially molten layer (the asthenosphere) that moves because of mantle convection. Heat from Earth’s interior creates currents that cause rock to rise in some places and sink in others. These convective motions push and pull the rigid plates that make up the lithosphere, setting them in motion.

Where those plates meet, their movements generate natural hazards. At plate boundaries, rocks can stick and then snap free, producing earthquakes. When one plate sinks beneath another (subduction) or when magma forms and rises at divergent or transform boundaries, volcanoes can erupt. Large undersea earthquakes or volcanic explosions can displace huge amounts of water, creating tsunamis.

So the driving idea is mantle convection in the asthenosphere moving the plates, with their interactions at boundaries producing earthquakes, volcanoes, and tsunamis. The other statements misidentify the heat source or the link to hazards—for example, radiometric decay isn’t the direct mechanism for plate motion, and magnetic field changes or solar heating don’t drive tectonic hazards in the same way.