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.
Professor Tan catalogued the slow-slip events that occurred between 2006 and 2016, and found that the weak tremors clusters follow a power-law spatial and temporal decay similar to earthquake aftershock sequences. These slow-slip events (SSEs) have smaller stress drop and rupture velocity, but follow similar magnitude-frequency, moment-area, and moment duration scaling as regular earthquakes. The study gives scientists a clearer picture of how cycles of energy buildup and release occur along faults, hoping to improve our ability to forecast earthquakes.