The largest earthquake ever recorded lasted for only about ten minutes. But two decades ago, scientists discovered that faults, the surfaces where earthquakes occur, can slide past each other very slowly sometimes. The slow earthquake, occurs deep in the earth and releases energy at slow pace, can last for weeks or longer. Professor Tan Yen Joe of Earth System Science Programme recently analysed hundreds of thousands of weak tremors emanating from the San Andreas Fault in California and found that slow earthquakes behave similarly to regular earthquakes.