We calculate the actual speed of the tsunami by measuring the water depth at a point in time when the tsunami passes by. A tsunami's ability to maintain speed is directly influenced by the depth of the water. A tsunami moves faster in deeper water and slower in shallower water. So unlike a normal wave, the driving energy of a tsunami moves through the water as opposed to on top of it. Therefore, as a tsunami moves though deep water at hundreds of miles an hour, it is barely noticeable above the waterline. A tsunami is typically no more than 3 feet (1 meter) high until it gets close to shore. Once a tsunami gets close to shore, it takes its more recognizable and deadly form.
Adult head lice can live for approximately 24 hours away from a host, according to the Centers for Disease Control. Nymphs, or young head lice, can live for only several hours away from a host. Lice eggs are less dependent on a host, and they can live for up to one week without a host. Continue Reading.
Head lice survive less than one or two days if they fall off the scalp and cannot feed. Head lice eggs (nits) cannot hatch and usually die within a week if they do not remain under ideal conditions of heat and humidity similar to those found close to the human scalp. The head lice may have become resistant to the treatment. 2  If the treatment used does not kill the head lice, your health care provider and pharmacist can help you be sure the treatment was used correctly and may recommend a completely different product if they think the head lice are resistant to the first treatment.