History of the Republic of China its remaining islands in Fujian as vital for any future campaign to defeat the PRC and retake mainland China. On 3 September 1954, the First Taiwan Strait Crisis began when the PLA started shelling Quemoy and threatened to take the Dachen Islands. On 20 January 1955, the PLA took nearby Yijiangshan Island, with the entire ROC garrison of 720 troops killed or wounded defending the island. On January 24 of the same year, the United States Congress passed the Formosa Resolution authorizing the President to defend the ROC's offshore islands. The First Taiwan Straits crisis ended in March 1955 when
Geology of Taiwan Emei Township, Hsinchu County. The second deadliest was a 7.3 quake that ruptured the Chelongpu Fault (車籠埔斷層) on 21 September 1999, known as the "921 earthquake". On 4 March 2010 at about 01:20 UTC, a magnitude 6.4 earthquake hit southern Taiwan. The seismic hazard map for Taiwan by the USGS shows 9/10 of the island as the highest rating (most hazardous). The offshore features include the Kaoping Slope extending off the southwest coast of Taiwan into the South China Sea. This is emerging from the sea over time to extend the island. The Henchung Ridge extends south from the Hengchun