环境地质学第二章.pptVIP

环境地质学Environmental Geology 地球内部过程 Plate Tectonics Geologic Tectonics Earthquake Tsunamis海啸 and Coastal Flooding 地球内部过程 Earthquake 地球内部过程 Earthquake Oft the teeming浇铸 earth① Is with a kind of colic pinchd挤压 and vexd烦恼 By the imprisoning of unruly wind Within her womb发源地; which for enlargement striving抗争 Shakes the old bedlam疯人院 earth and topples down Steeples教堂尖塔 and moss苔-grown towers. William Shakespeare 地球内部过程 Earthquake “This earthquake is not a new thing,” replied Pangloss. “The town of Lima felt the same shocks in America last year, similar causes produce similar effects; there must certainly be a train of sulfur underground from Lima to Lisbon... all this is for the best.”② 地球内部过程 Earthquake 地球内部过程 Earthquake Epicenter震中 and Focus震源: When an earthquake occurs, seismic waves travel in all directions from the focus, the region where the earthquakes energy originates. The foci焦距、震源 of most earthquakes are concentrated in the earths crust, which is about 50 km thick under continents. Earthquakes are classified according to focal depths a) 0-60 km are shallow, b) 60-300 km are intermediate, and c) deep earthquakes may reach depths of 700 km. The epicenter of an earthquake is the point on the earths surface directly above the focus. . 地球内部过程 Earthquake Epicenter震中 and Focus震源: (中国人发明的地震仪） The scientific study of earthquakes began with the Chinese as early as 132 A.D. Chang Heng, a Chinese astronomer and mathematician, invented an earthquake weathercock风标, an instrument consisting of an array of loosely held balls in the mouths of eight dragons facing at angles of 45° from one another. An internal mechanism, activated by even a slight tremor, opened the mouth of a dragon, releasing a ball which fell into the open mouth of a toad蟾蜍below, sounding an alarm. The direction of th