Earthquakes and Seismographs
An earthquake is the vigorous and intense shaking of the Earths surface. They happen very frequently. Depending on where you live, you can feel them more or less often. The worlds largest earthquake was the 1960 Valdivia Earthquake at a magnitude of 9.5! These can cause tremendous amounts of damage to civilian life, and it can take years to get the place back to normal.
But why do earthquakes happen in the first place?
Well, Earth’s crust isn’t an immobile and solid shell that doesn’t move. The Earth is made of constantly moving tectonic plates. These tectonic plates usually move really slowly, but abrupt shifts of these plates are what cause earthquakes all around the world.
Scientists known as seismologists study earthquakes and record seismic activity in the Earth. They use seismographs to measure earthquakes to detect them and record the grounds motion during the quakes.
How do seismographs work then?
Seismographs have a mass that is mounted on a suspension, which remains unmovable during an earthquake. When the seismograph moves under the load, it records the vibrations using the pen as it moves on the graph tape.
How do we interpret the seismographs?
We use the Richter Scale to calculate the earthquakes magnitude by using the amplitude of the largest seismic wave that was recorded by the seismograph. Tinier earthquakes have a smaller value on the Richter Scale (closer to 0), while larger earthquakes have a bigger value (closer to 9 and 10).
Through our continuous study and improved understanding of earthquakes through seismographs and the Richter Scale, we understood that earthquakes couldn’t just be prevented, so we had to learn how to live with them. Buildings were slowly rebuilt and made to withstand the power of earthquakes, so the area wouldn’t be in total disaster after each one. Architects have been able to increase the seismic resistance of many buildings in active earthquake regions to tackle this problem.
They made sure buildings were separated from the ground by rolls, springs, or rubber, so they can move independently from the Earth. Tuned mass dampers are large concrete blocks that were mounted onto tall buildings like skyscrapers to dampen the vibrations and reduce the acceleration of the buildings during the earthquake.
All in all, we have learned how to live with earthquakes and detect them using seismology. Want to learn more about seismology? Here’s a fun kit MEL Science put together where you can make an actual seismograph!
Have fun building!
