Before you watch
Breaking news: Magnitude-6.4 earthquake shocks Kaohsiung,Taiwan.
臺灣高雄發生芮氏6.4級地震 釋放能量相當於兩顆原子彈
Background
為什麼臺灣多地震？
臺灣位於環太平洋地震帶（ring of fire）太平洋板塊、菲律賓板塊和歐亞板塊相互作用的邊界地區
The Ring of Fire is an area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur.
About 90% of the world's earthquakes occur along the Ring of Fire.
測定的地震等級的儀器是什麼？
地震儀（Seismometers )
Seismometers are instruments that measure motion of the ground, including those of seismic waves generated by earthquakes.
世界上第一架測驗地震的儀器-中國東漢科學家張衡發明的候風地動儀
Zhang Heng's seismoscope Houfeng Didong Yi
分析地震的三要素
Three Essential Factors of Ground Motion
地震的震級大小（magnitude scale）+震中位置(epicentral area )+ 地震發生的時間(timing).
震級通常用字母M表示（magnitude ), 震級是指地震的大小，是表徵地震強弱的量度，是以地震儀測定的每次地震活動釋放的能量多少來確定的。中國使用的震級標準，是國際上通用的裡氏分級表（Richter magnitude scale）.
Vocabulary
Kaohsiung 高雄，臺灣第二大城市，位於臺灣南部
While you watch
Video#1 Epicenter in Kaohsiung with a depth of 15 km(0'52'')
Video#2 Science Behind an Earthquake Warning System（1'26''）
Fill in the blanks（100%）
CHAD MYERS, AMS METEOROLOGIST
1.An e___________ warning system for earthquakes is e___________ and also complex. Part of the problem is we don’t have a system that can p___________ the earth is going to move. Our warming system is based on the fact that the earth is already m___________ and then if you’re f___________ away from that epicenter, we can give you some time to prepare. It’s a m__________ time but some time.
2.Unlike a tornado warning where Doppler Radar can see the rotation and issue a warning before the t__________, an earthquake warning happens when the earth is already shaking. Another l__________ is how close the s__________ is to the epicenter. If the sensor is 10 miles away from the epicenter, it takes ______ seconds to get to that sensor. So, the more sensors we get, the better the lead time we』ll get as well.
3.If we get 10 s__________ notice of an earthquake that’s happening, especially a big one, you can open up the e__________ on the nearest floor. You can stop t__________. You can stop all those things that are moving before the s__________ gets there.
4.This entire system works because of the speed of l__________, or the speed of the warning going down the line, is _________ miles per second. The earth as it’s wiggling and shaking along is going at _______ miles per second.
5.So, if you’re _____ miles away, your warning could be ______ seconds. It’s _____ seconds that could save your life.
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