Why measure fault line stresses from orbit

Reuters : Locating silent earthquakes-- slow-moving events tracked by satellites measuring subtle changes on the earth’s surface because they do not broadcast shock waves -- may help scientists better predict the probability of more active tremors, says a new report in this week’s Nature. The quakes appear to build pressure on fault zones, contributing to weak magnitude-two and magnitude-three earthquakes, says Stanford geophysicist Paul Segall.