Storm surge is caused by typhoons, temperate cyclones, cold fronts, strong winds and sudden changes in air pressure and other strong weather systems caused by the sea surface anomalous rise and fall phenomenon, also known as storm surge or meteorological tsunami. Storm surge is a gravity long wave, the period from a few hours to a few days, between the earthquake tsunami and low-frequency ocean tides, the amplitude (i.e., the height of the tide of the storm surge) is generally a few meters, the maximum can be up to <2-3> kilometers. It is a natural disaster in coastal areas, it and the accompanying wind and waves can cause greater disasters. Usually the storm surge is divided into temperate cyclones caused by temperate storm surge (such as the northern sea area of China) and tropical storms (typhoons) caused by tropical storm surge (such as the southeast coast of China) two categories.
Disastrous waves are waves in the ocean produced by the wind with catastrophic damage, the force of which can reach 30-40 tons per square meter. Sea ice refers to all the ice on the ocean, including saltwater ice, river ice and icebergs. In the region of serious ice conditions or unusually cold winter often appear serious ice phenomenon, so that the coastal ports and waterways frozen, to the coastal economy and people's lives and property safety hazards. Continental glaciers or shelf ocean slipped into the sea after the break into the huge ice, exposed to the sea surface height of more than 5 meters known as the iceberg wheel that is the first voyage in the North Atlantic Ocean hit this iceberg and sank.
Red tide refers to the marine plankton in certain conditions, the phenomenon of sudden reproduction caused by seawater discoloration, it is also a marine pollution phenomenon. Most of the red tide occurs in the inner sea, estuaries, harbors or waters with upwelling, especially warm inland waters. The color of red tide is determined by the pigmentation of dominant and non-planktonic species that form red tide. For example, red tides formed by luminous algae are red, while green flagellate algae blooms are green and diatoms tend to be brown. Red tide is actually a collective term for all kinds of color tides. Red tide can kill marine animals and is very harmful. Tsunamis are huge waves that are stirred up by underwater earthquakes, volcanic eruptions, or underwater collapses and landslides. Destructive earthquake tsunami conditions are: vertical movement in the seismic tectonic movement; depth of epicenter is less than 20-50 km; Richter magnitude to be greater than 6.5 and no seafloor deformation of the seismic shock or the seafloor elastic vibration, which can cause weaker tsunamis. Underwater nuclear explosions can also produce man-made tsunamis. Tsunami on the coastal areas of people, animals, trees, housing construction, harbors and bays mainly occur in the Pacific coast of Japan, the Pacific Ocean in the west, south and southwest, the Hawaiian Islands and the Aleutian Islands coast. Although the tsunami hazard is huge, but it formed a limited frequency, especially in the people can be on it since, the harm caused by its has been greatly reduced