Unit4 Natural disasters Period 2 Reading and Thinking 课件-【新教材】人教版（2019）高中英语必修第一册

Unit 4 Natural Disasters Period 2 Reading and Thinking Reading and Thinking Live to tell: Raising Awareness, Reducing Mortality. —United Nations International Strategy for Disaster Reduction (2016) 劫后余生：提高认识，减少死亡。 《联合国减少灾害国际战略》(2016年) THE NIGHT THE EARTH DIDN'T SLEEP THE NIGHT THE EARTH DIDN'T SLEEP Reading and Thinking What is an earthquake? An earthquake a shaking of the ground caused by movement of the Earth's crust(地壳). Pre-reading Reading and Thinking What's earthquake magnitude? 地震震级 是指地震大小，通常用字母M表示。地震愈大，震级数字也愈大，世界上最大的震级为9.5级。 地震释放的能量来表示地震的大小，即地震的震级。震级大的地震，释放的能量多；震级小的地震，释放的能量少。 中国一般采用里氏震级。 通常小于2.5级的地震称为小地震， 2.5-4.7之间的地震称为有感地震 震级每相差1.0级，能量相差大约30倍。 Reading and Thinking Earthquake prediction Earthquake prediction is the prediction of the time, place, magnitude and impact of future destructive earthquakes. Earthquake prediction should pay attention to three elements: time, place and magnitude of earthquake. 地震预报是对未来破坏性地震发生的时间、地点、震级和地震影响的预测。地震预报需要注意三要素：发震时间、地点、震级。 Reading and