Depending on the size of the mainshock, aftershocks can continue for weeks, months, and even years after the mainshock! What causes earthquakes and where do they happen?Ī simplified cartoon of the crust (brown), mantle (orange), and core (liquid in light gray, solid in dark gray) of the earth. These are smaller earthquakes that occur afterwards in the same place as the mainshock. Mainshocks always have aftershocks that follow. The largest, main earthquake is called the mainshock. Scientists can’t tell that an earthquake is a foreshock until the larger earthquake happens.
These are smaller earthquakes that happen in the same place as the larger earthquake that follows. The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter. The surface where they slip is called the fault or fault plane. A normal (dip-slip) fault is an inclined fracture where the rock mass above an inclined fault moves down (Public domain.)Īn earthquake is what happens when two blocks of the earth suddenly slip past one another.