Many people are aware that large earthquakes are often followed by a sequence of aftershocks as stresses are redistributed in the surrounding area. Many may not be aware that there are also sequences of earthquakes that occur before most large earthquakes. Many people are aware that large earthquakes are often followed by a sequence of aftershocks as stresses are redistributed in the surrounding area. Many may not be aware that there are also sequences of earthquakes that occur before most large earthquakes. Earth Sciences Phys.org – latest science and technology news stories