Two geologists explain.
Ice is extremely heavy, and glaciers are massive sheets of ice. Professor Patrick Wu (Univ of Alberta) says that the weight of the ice suppresses the earthquakes, but when glaciers begin to melt, that pressure is released, and "earthquakes get triggered," as well as tsunamis (which are underwater earthquakes). He adds that melting ice in Antarctica is already triggering earthquakes and "underwater landslides."
Prof. Bill McGuire (Univ. College of London) says, "All over the world, evidence is stacking up that changes in global climate can and do affect the frequencies of earthquakes, volcanic eruptions, and catastrophic seafloor landslides."
This is only the tip of the iceberg, folks, if you'll excuse the expression. What's happening in Haiti and Chile will be routine news items ten years from now.