Here are some fascinating facts about the study of seismic activity (seismology):
1. Earthquakes Happen More Often Than You Think
- Over 500,000 detectable earthquakes occur each year, but only about 100,000 can be felt, and only 100 or so cause significant damage.
2. The Earth Rings Like a Bell
- Large earthquakes (magnitude 7+) make the entire planet vibrate like a ringing bell, with seismic waves traveling around the globe multiple times.
3. Earth’s Core Affects Seismic Waves
- Seismic waves change speed and direction when passing through different layers of Earth, helping scientists map the liquid outer core and solid inner core.
4. Animals Sometimes Sense Earthquakes Before Humans
- There are reports of animals acting strangely before quakes, possibly due to detecting P-waves (fast, weak seismic waves) or changes in groundwater.
5. The Largest Recorded Earthquake
- The 1960 Valdivia earthquake in Chile (magnitude 9.5) is the strongest ever recorded. It shifted Earth’s axis and shortened the length of a day by microseconds.