Ocean Hazards
Tsunamis
- A tsunami is a series of ocean waves caused by an underwater earthquake, landslide, or volcanic eruption. More rarely, a tsunami can be generated by a giant meteor impact with the ocean. These waves can reach heights of over 100 feet.
- Scientists can accurately estimate the time when a tsunami will arrive almost anywhere around the world based on calculations using the depth of the water, distances from one place to another, and the time that the earthquake or other event occurred.
- When tsunamis hit shallow water (often near the coast) they slow down but increase in height.
Rip Current:
- When wind and waves push water toward the shore, that water is often forced sideways by the oncoming waves.This water streams along the shoreline until it finds an exit back to the sea or open lake water.
- A more theoretical description involves a quantity known as radiation stress .This is the force (or momentum flux) exerted on the water column by the presence of the wave.
- Although a rare event, rip currents can be deadly for non-swimmers as well , a person standing waist deep in water can be dragged into deeper waters, where they can drown if they are unable to swim and are not wearing a flotation device .
- A swimmer caught in a rip current should not attempt to swim back to shore directly against the rip.The swimmer should quickly recognise what is happening, then remain calm and swim parallel to the shore until he or she is outside of the current.
Jellyfish
- Jellyfish stings in Australia can cause death, with there being several venomous species of jellyfish, such as the box jellyfish and Irukandji Jellyfish. Box jellyfish have caused more than 60 deaths in Australia in the past hundred years.
- Its venom is very powerful. Researchers conjecture that its venom possesses such potency to enable it to quickly stun its prey, which consists of small and fast fish.
- The average jellyfish has stingers only on its tentacles but the Irukandji also has stingers on its bellpiece.
- Irukandji syndrome is produced by a small amount of venom and induces excruciating muscle cramps in the arms and legs, severe pain in the back and kidneys, a burning sensation of the skin and face, headaches, nausea, restlessness, sweating, vomiting, an increase in heart rate and blood pressure, and psychological phenomena such as the feeling of impending doom.]The syndrome is in part caused by release of catecholamines. The venom contains a sodium channel modulator.