Katy Tur @KatyTurNBC
RT @DrLucyJones: A quake is called an aftershock as long as the rate of events is above the rate that was there before the mainshock. For a… — PolitiTweet.org
Rob Rainbolt @Rob_Rainbolt
@DrLucyJones How many years can pass before a quake is considered a new shock?