Comment: 02:10 - 03:26 (01:16)
Source: Annenberg/CPB Resources - Earth Revealed - 9. Earthquakes
Keywords: "radioactive decay", heat, energy, plate, friction, lithosphere, earthquake, mountain, orogeny, uplift, erosion, river, water, flora, fauna
Our transcription: Radioactive decay generates the heat, energy, which ultimately powers movements of Earth's rocky tectonic plates.
The friction between the rough edges of these slowly moving segments of the Earth's lithosphere results in a series of jerky starts and stops, which is the direct cause of most major earthquakes.
The same heat engine that produces earthquakes is the driving force raising the world's great mountain ranges.
If this uplift did not take place, the relentless force of erosion would reduce the Earth's landscape to a single flat plane.
Without the present range of elevations, rivers would lose their principal sources of water.
The land would ultimately erode down to tide level, and most of the diversity in the world's flora and fauna would disappear.
And yet, while there are indirect benefits to living in a world with earthquakes, it's the capacity of tremors to violently disrupt human activity that commands our attention.
Geology School Keywords