On August 1, 1975, a magnitude 6.1 earthquake at Oroville, California, was attributed to seismicity from a large earth-fill dam and reservoir recently constructed and filled. The filling of the Katse Dam in Lesotho, and the Nurek Dam in Tajikistan is an example. In Zambia, Kariba Lake may have provoked similar effects. The 2008 Sichuan earthquake, which caused approximately 68,000 deaths, is another possible example. An article in Science suggested that the construction and filling of the Zipingpu Dam may have triggered the earthquake. Some experts worry that the Three Gorges Dam in China may cause an increase in the frequency and intensity of earthquakes. Mining Mining affects the stress state of the surrounding rock mass, often causing observable deformation and seismic activity. A small portion of mining-induced events are associated with damage to mine workings and pose a risk to mine workers. These events are known as rock bursts in hard rock mining, or as bumps in underground coal mining. A mine's propensity to burst or bump depends primarily on depth, mining method, extraction sequence and geometry, and the material properties of the surrounding rock. Many underground hardrock mines operate seismic monitoring networks in order to manage bursting risks, and guide mining practices. Seismic networks have recorded a variety of mining-related seismic sources including: Shear slip events (similar to tectonic earthquakes) which are thought to have been triggered by mining activity. Notable examples include the 1980 Bełchatów earthquake and the 2014 Orkney earthquake. Implosional events associated with mine collapses. The 2007 Crandall Canyon mine collapse and the Solvay Mine Collapse are examples of these. Explosions associated with routine mining practices, such as drilling and blasting, and unintended explosions such as the Sago mine Disaster. Explosions are generally not considered "induced" events since they are caused entirely by chemical payloads. Most earthquake monitoring agencies take careful measures to identify explosions and exclude them from earthquake catalogs. Fracture formation near the surface of excavations, which are usually small magnitude events only detected by dense in-mine networks. Slope failures, the largest example being the Bingham Canyon Landslide. Waste disposal wells Injecting liquids into waste disposal wells, most commonly in disposing of produced water from oil and natural gas wells, has been known to cause earthquakes. This high-saline water is usually pumped into salt water disposal (SWD) wells. The resulting increase in subsurface pore pressure can trigger movement along faults, resulting in earthquakes.