NUMERICAL MODEL FOR THE KRAKATOA HYDROVOLCANIC EXPLOSION AND TSUNAMI
NUMERICAL MODEL FOR THE KRAKATOA HYDROVOLCANIC EXPLOSION AND TSUNAMI
复制标题
喀拉喀托火山喷发和海啸的数值模型
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
M. Gittings
中科院分区：
文献类型：
--
作者：
C. Mader;M. Gittings
1883年8月27日，喀拉喀托火山爆炸，摧毁了5平方英里的土地，留下了一个3.5英里宽、200-300米深的陨石坑。33英尺高的海啸袭击了安杰尔和梅拉克，摧毁了这两个城镇，造成1万多人死亡。在梅拉克，海浪高出海平面135英尺，将100吨珊瑚礁冲上了海岸。海啸浪潮席卷了300个沿海城镇和村庄，造成4万人死亡。海啸在印度孟买退去，并在斯里兰卡造成一人死亡。海啸是由火山喷发以及与之相关的冲击波和火山碎屑流引起的。火山喷发是由高温岩浆与地下水相互作用产生的。它是在1963年冰岛外海爆发后被称为Surtseyan的。水会闪现成水蒸气，然后爆炸式地膨胀。液态水在恒定体积下变成水气，产生30,000个大气压的压力。喀拉喀托火山水压爆炸采用完整的可压缩流体力学程序SAGE进行模拟，该程序包含了爆炸的高压物理。火山喷发中的水被描述为被岩浆加热到1100开尔文或19千卡/摩尔的液态水。高温水是一种炸药，热的液态水变成了水煤气。BKW稳态爆轰的峰值压力为89千巴，传播速度为5900米/秒，水被压缩到1.33克/毫升。观测到的喀拉喀托海啸周期不到5分钟，波长不到7公里，因此迅速衰减。远场海啸波可以忽略不计。火山喷发产生的空气冲击波传播到世界各地，并与海洋相结合，导致世界各地的验潮仪记录到了这次爆炸。
Krakatoa exploded August 27, 1883 obliterating 5 square miles of land and leaving a crater 3.5 miles across and 200-300 meters deep. Thirty three feet high tsunami waves hit Anjer and Merak demolishing the towns and killing over 10,000 people. In Merak the wave rose to 135 feet above sea level and moved 100 ton coral blocks up on the shore. Tsunami waves swept over 300 coastal towns and villages killing 40,000 people. The sea withdrew at Bombay, India and killed one person in Sri Lanka. The tsunami was produced by a hydrovolcanic explosion and the associated shock wave and pyroclastic flows. A hydrovolcanic explosion is generated by the interaction of hot magma with ground water. It is called Surtseyan after the 1963 explosive eruption off Iceland. The water flashes to steam and expands explosively. Liquid water becoming water gas at constant volume generates a pressure of 30,000 atmospheres. The Krakatoa hydrovolcanic explosion was modeled using the full Navier-Stokes AMR Eulerian compressible hydrodynamic code called SAGE which includes the high pressure physics of explosions. The water in the hydrovolcanic explosion was described as liquid water heated by the magma to 1100 degree Kelvin or 19 kcal/mole. The high temperature water is an explosive with the hot liquid water going to a water gas. The BKW steady state detonation state has a peak pressure of 89 kilobars, a propagation velocity of 5900 meters/second and the water is compressed to 1.33 grams/cc. The observed Krakatoa tsunami had a period of less than 5 minutes and wavelength of less than 7 kilometers and thus rapidly decayed. The far field tsunami wave was negligible. The air shock generated by the hydrovolcanic explosion propagated around the world and coupled to the ocean resulting in the explosion being recorded on tide gauges around the world.