(OCTOBER 25, 2019) An earthquake is a sudden movement of the Earth's surface. They can be very dangerous. The ground shakes, and there can often be heavy damage to buildings, bridges, and other structures. When they happen in the water, they can create giant waves called tsunami.
Scientists measure earthquakes. They use the Richter scale to measure its magnitude (strength). A small earthquake receives a smaller magnitude number. A large earthquake receives a larger magnitude number. Earthquakes with a magnitude between 5.5 and 8.9 cause a lot of damage.
Earthquakes happen in Oregon, too. In fact, there have been seven small earthquakes in the month of October. Most have been in the ocean near the Oregon Coast.
The seven earthquakes in Oregon in October were: