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The tsunami overwhelmed the coastal village, leaving it completely submerged.
海啸淹没了整个沿海村庄,使其完全被淹没。
Damage from the 2011 earthquake and tsunami sits untouched.
2011年地震及海啸造成的损害仍然维持在那里。
The tech magazines told us a tsunami was coming.
科技杂志告诉我一场海啸就要来了。
Tsunami alerts and evacuation orders have been lifted.
海啸警报和疏散命令已取消。
Japan's Meteorological Agency has issued tsunami advisories following two earthquakes.
日本气象厅在两次地震后发布了海啸预警。
Actually, you wouldn't notice a tsunami at all.
事实上,你根本不会注意到海啸。
They made that decision after an earthquake and tsunami damaged the Japanese plant in 2011.
2011年地震和海啸破坏了日本核电站后,德国官方就做出了这个决定。
What's more, it takes up to an hour for a single tsunami to roll by.
更重要的是,一次海啸最多一个小时就过去了。
One warning sign of a tsunami is water right along the coast rapidly receding.
海啸的一个预兆就是海岸上的海水迅速退潮。
When an earthquake strikes, the erratic movement of the ocean floor can generate a tsunami.
当地震发生时,海床上的不稳定的震动就会产生海啸。
They have a lot of earthquakes, but sometimes they get a tsunami.
日本经常会发生地震,但有时日本会遭受海啸。
中国最早在汉朝就已有对海啸的纪录,在中国古书记载的海溢、海潮溢、海吼、海唑、海沸都是指海啸。
这是一种波长极长的重力波。若是发生于在近岸浅水海域,波浪因深度渐浅而波高骤增,可造成严重灾害。此波于大洋中传递极快,每秒速度可超过二百公尺。在地震发生处的波动可能只有0.1公尺到5公尺的高度,波长却可能是1500公里。随着水波传到岸边波长会缩短到5公里,高度却可达到50公尺。
海潮暴涨有可能是海啸所引起,也可能是台风所引起。近地海啸所引起的海潮暴涨通常伴随着地震,远洋地震所引起的海啸则不会感受到地震动。而台风所引起的海啸则伴随强风。史籍上若提到地大震,之后海潮暴涨,则海啸的可能性极大。然而多数记载只提到海潮暴涨,并无其他说明,是否是地震海啸就有待进一步探讨。因此将史籍上所述之海啸或疑海啸,以海啸信度表示其发生之可能性。
当海啸从较宽广较深的海域传到海岸时,则会变形。当海水传到岸边时,因为水深变浅,所以波浪的传递速度变慢。当前一波海浪的速度变慢后,后一波因为速度未降追了上来,所以变成波高变高。所以即便在深水区不高的波浪,到了岸边波高却会增加许多。
当海啸到达海岸时,看来很像加速版的潮汐的起落。如果波高太高时波浪则会碎掉,或是可以看到很高的水墙。不过海啸一般很少在岸边成为如塔般很高的水墙,或是看到明显的破浪,因为有时波浪是在离岸较远处就已破碎了。另外海啸来袭时波浪若进入浅水海湾或河流出海口,也可能看到类似阶梯状波浪的涌潮(bore)出现。这些都会造成海岸边的海水高度升高。若震央较近海岸时,甚至有观测到升高相当于十层楼高的。
与地震一样,有过多次尝试创建衡量海啸强度或大小的等级,使得不同事件之间可以比较。
这里h是最大海啸波幅(单位:米,m),由距离震中距离 为R的验潮仪测得;a,b和D是用于使the Mt等级尽可能匹配矩震级(moment magnitude scale)的常数。
美国西海岸·阿拉斯加海啸警报中心(WCATWC;暂译)中,将美国及其周边地区依照海岸地形等要素划分为11个区域。各区域分别有2种(或1种乃至没有)TIS(Tsunami Information Statement,海啸情报)、3种(或1种)Warning(警报),共1~5级警报。
气象厅根据预测的波浪高度,将海啸警报区分为以下2类3种发表。此外,由于报道“大海啸海啸警报”比较拗口,简称为“大海啸警报”。
海啸警报·注意报是将日本沿岸地区分割为不同区块(称为海啸预报区),指定地区进行发表。
发布海啸警报、注意报时,将会发布包括抵达岸边的时刻、预测的海浪高度、各地满潮时刻、到达时所观测到的波高等的“海啸信息”。
近年来较大规模的海啸有:
Numerous terms are used in the English language to describe waves created in a body of water by the displacement of water; however, none of the terms in frequent use are entirely accurate.
The energy released produces tsunami waves.
The cause of the Storegga sediment failure is unknown. Possibilities include an overloading of the sediments, an earthquake or a release of gas hydrates (methane etc.).
Tsunamis cause damage by two mechanisms: the smashing force of a wall of water travelling at high speed, and the destructive power of a large volume of water draining off the land and carrying a large amount of debris with it, even with waves that do not appear to be large.
The velocity of a tsunami can be calculated by obtaining the square root of the depth of the water in meters multiplied by the acceleration due to gravity (approximated to 10 m sec). For example, if the Pacific Ocean is considered to have a depth of 5000 meters, the velocity of a tsunami would be the square root of √5000 x 10 = √50000 = ~224 meters per second (735 feet per second), which equates to a speed of ~806 kilometers per hour or about 500 miles per hour. This formula is the same as used for calculating the velocity of shallow waves, because a tsunami behaves like a shallow wave as it peak to peak value reaches from the floor of the ocean to the surface.
When the tsunami's wave peak reaches the shore, the resulting temporary rise in sea level is termed run up. Run up is measured in metres above a reference sea level. A large tsunami may feature multiple waves arriving over a period of hours, with significant time between the wave crests. The first wave to reach the shore may not have the highest run up.
A typical wave period for a damaging tsunami is about 12 minutes. This means that if the drawback phase is the first part of the wave to arrive, the sea will recede, with areas well below sea level exposed after 3 minutes. During the next 6 minutes the tsunami wave trough builds into a ridge, and during this time the sea is filled in and destruction occurs on land. During the next 6 minutes, the tsunami wave changes from a ridge to a trough, causing flood waters to drain and drawback to occur again. This may sweep victims and debris some distance from land. The process repeats as the next wave arrives.
As with earthquakes, several attempts have been made to set up scales of tsunami intensity or magnitude to allow comparison between different events.
where h is the maximum tsunami-wave amplitude (in m) measured by a tide gauge at a distance R from the epicentre, a, b and D are constants used to make the Mt scale match as closely as possible with the moment magnitude scale.
As a direct result of the Indian Ocean tsunami, a re-appraisal of the tsunami threat for all coastal areas is being undertaken by national governments and the United Nations Disaster Mitigation Committee. A tsunami warning system is being installed in the Indian Ocean.