CALIFORNIA — Along coastal California, the possibility of earthquakes and landslides is commonly prefaced by the phrase, “not if, but when.” This precarious reality is now a bit more predictable thanks to researchers at UC Santa Cruz and The University of Texas at Austin, who found that conditions known to cause slip along fault lines deep underground also lead to landslides above. …In California, where slow-moving slides are constant and cost hundreds of millions of dollars annually, this represents a major step forward in the ability to predict landslide movements—particularly in response to environmental factors like changes in groundwater levels. …”At a practical level, this study provides us with a framework for understanding how much motion to expect based on a change in rainfall, which leads to a change in water pressure in the ground that then translates into motion,” said Noah Finnegan, a professor of earth and planetary sciences.