Earthquakes and Tsunamis

Written by Sam Vaknin


Tsunami - a seismic sea wave - means in Japanese "harbor-wave". It is also misleadingly called "tidal wave". It is an ocean wave caused by an earthquake of magnitude 6.5 onrepparttar Richter scale (or greater) that occurs less than 50 kilometers beneathrepparttar 110087 seafloor. Tsunamis can also be caused by volcanic eruptions and by landslides.

Tsunami waves are followed by three to five oscillations ofrepparttar 110088 continental shelf waters. These convulsions may last up to a week. Ifrepparttar 110089 initial wave reachesrepparttar 110090 shore at its trough phase,repparttar 110091 water recede and exposerepparttar 110092 seafloor. This happened in Lisbon Port on November 1, 1755. A few minutes later,repparttar 110093 displaced waters return with energetic vengeance.

Inrepparttar 110094 ocean, tsunami waves are merely 0.5-2 meters high with a wavelength of up to 200 kilometers. Consequently, they are virtually impalpable though they move at speeds of up to 700 kilometers per hour. Asrepparttar 110095 waves nearrepparttar 110096 shoreline, friction withrepparttar 110097 shallow bottom reduces their velocity, shortens their wavelength, increases their amplitude and their height.

The tsunami wave that swept acrossrepparttar 110098 coasts of Indonesia, Sri Lanka, Thailand, India, and Africa on December 26, 2004 was 10-12 meters high. It traveled almost 6000 kilometers. It killed almost 150,000 people. An earthquake inrepparttar 110099 fjord-like Lituya Bay, Alaska, on July 9, 1958, generated a tsunami wave 524 meters (1719 feet) high, moving at a speed of 160 kilometers per hour. Luckily,repparttar 110100 area was largely uninhabited.

Other notable tsunamis:

In 1703 at Awa, Japan with more than 100,000 people dead.

On April 24, 1771, a tsunami caused by an underwater earthquake struckrepparttar 110101 Japanese island of Ishigaki (inrepparttar 110102 Ryuku chain). It was 85 meters high. It was so powerful that it hurled a 750 ton piece of coral to a distance of 2.5 kilometers inland.

Again in Japan, 27,000 people drowned in 1896, in a giant tsunami.

Inrepparttar 110103 wake ofrepparttar 110104 underwater volcanic eruptions that obliteratedrepparttar 110105 island of Krakatau (Krakatoa) on August 26-27, 1883, a wave 35 meters high swept acrossrepparttar 110106 East Indies killing in excess of 36,000 people.

Triggered by a submarine landslide, a tsunami at least 375 meters high struckrepparttar 110107 island of Lanai in Hawaii about 105,000 years ago.

The 1960 earhquake in Chile created tsunami waves that traveled more than 10,000 kilometers to Hilo, Hawaii. The 12 meters high water wall killed 61 people and destroyed many buildings.

The Seismic Sea Wave Warning System (SSWWS), based in Honolulu, is an early warning system coveringrepparttar 110108 entire, tsunami-prone, Pacific Ocean.


Little known facts about temblors:

The epicenter of an earthquake is notrepparttar 110109 same as its hypocenter (focus, point of origin within a fault-line). The epicenter isrepparttar 110110 point onrepparttar 110111 surface ofrepparttar 110112 Earth directly aboverepparttar 110113 focus. Dangerous, shallow-focus quakes originate 0-70 kilometers belowrepparttar 110114 surface. Less damaging deep-focus tremors occur between 70-700 kilometers down. Subduction zone earthquakes (likerepparttar 110115 one that gave rise torepparttar 110116 lethal tsunami on December 26, 2004) occur when one tectonic plate moves under another (subducts). There are interplate and intraplate quakes, which take place along plate boundaries or withinrepparttar 110117 fracturing crust of a single plate, respectively.

Earthquakes are not rare at all - several hundred earthquakes occur every day. There are about 1 million of them annually - of which 50,000 can be felt withoutrepparttar 110118 aid of instruments. Tremors ofrepparttar 110119 magnitude of Kobe in 1995 (which caused an estimated damage of $100 billion ) are measured 20 times in an average year.

The Encyclopedia Britannica (2005 edition) describes a "swarm" of such events thus:

"Inrepparttar 110120 Matsushiro region of Japan, for instance, there occurred between August 1965 and 1967 a series of hundreds of thousands of earthquakes, some sufficiently strong (up to local magnitude 5) to cause property damage but no casualties. The maximum frequency was 6,780 small earthquakes on April 17, 1966."

The Pacific ocean isrepparttar 110121 unhappy recipient of well over 80 percent of allrepparttar 110122 energy released by earthquakes worldwide. Japan alone suffers from 1500 tremors annually (of which two thirds are greater than 3.5 in magnitude). Fault lines abound and new ones are discovered frequently. One fault line runs under 125th street in Manhattan, New-York.

Still, inrepparttar 110123 last 5 centuries, all earthquakes combined killed less than one tenthrepparttar 110124 victims of World War II - and this includesrepparttar 110125 240,000 who died inrepparttar 110126 1976 Tang-Shan, China event.

Earthquakes are composites of:

I. Primary (or compression) and secondary (or shearing) body waves (that travel inrepparttar 110127 rocks underrepparttar 110128 surface ofrepparttar 110129 Earth at speeds of up to 7 kilometers per second and frequencies of between 20 Hertz and one vibration per 54 minutes)


II. Two types of surface waves, named after British physicist Lord Rayleigh and British geophysicist A. E. H. Love (with frequencies of 1-0.005 Hertz).

Some earthquakes are caused by human activities (such asrepparttar 110130 filling of water reservoirs behind dams, injecting water into deep wells, and underground nuclear tests). More than 600 tremors were recorded inrepparttar 110131 decade followingrepparttar 110132 filling of Lake Mead behind Hoover Dam onrepparttar 110133 Nevada-Arizona state border.

Use Natural Cleaners to remove the Toxic Risk from your home

Written by Chris Western

Maybe you live in a nice house smelling of alpine meadows with a sparkling bathroom, lovely clean and polished surfaces.

What if someone were to come into your lovely shining home and mix up a cocktail of unknown chemicals for you and your family to distribute aroundrepparttar house. Would you allow it? Of course not. You wouldn’t want potentially poisonous chemicals around your house to pose a risk of contamination torepparttar 110086 air you breath or to what your family eat & drink.

Disturbingly however, they may already be there.

Brought into your home as unseen and unlabelled additives in many ofrepparttar 110087 cleaning products that are commonly available to keep your house sparkling clean.

You may think thatrepparttar 110088 ingredients in household products are safe having been tested byrepparttar 110089 authorities and cleared for use because they are known to pose no threat. Sadly, nothing could be further fromrepparttar 110090 truth.

In reality many hazardous chemicals are added to consumer goods. Some of these are known to be hazardous, but current legislation allows for their continued use. This is becauserepparttar 110091 regulations work on ‘safe limits’ of exposure for individual products. The weaknesses of this approach are that they do not add up accumulated doses from multiple sources of exposure, and neither do they take into accountrepparttar 110092 effect on children and unborn infants,repparttar 110093 dosages allowed being based on adult tolerance levels.

A study byrepparttar 110094 European Environment Agency carried out in 1998 noted that ”widespread exposures to low levels of chemicals may be causing harm, possibly irreversibly, particularly to sensitive groups such as children and pregnant women…”

Consider some of these common types of household cleaning product and what threat they may carry.

Air Fresheners

Many of these products contain formaldehyde and phenol. The former is a known carcinogen andrepparttar 110095 later can cause skin irritation.

Antibacterial Cleaners

May contain triclosan, which has been connected to liver damage and is readily absorbed throughrepparttar 110096 skin

Carpet and upholstery shampoo

Many contain perchlorethane, which is a carcinogen which damagesrepparttar 110097 liver, kidneys and central nervous system. Ammonium hydroxide may also be present which is a corrosive compound, extremely irritating torepparttar 110098 eyes, skin and respiratory system.

Dishwasher detergents

Studies have shown these to berepparttar 110099 foremost cause of home poisoning incidents. Most products containrepparttar 110100 dry form of chlorine. Scientists and engineers do not handle chlorine without protective clothing. It is extremely dangerous and can very easily be lethal. Indeed, it wasrepparttar 110101 first agent to be used in World War One as a chemical warfare agent.

Dishwashing liquids are labelled ‘harmful if swallowed’ yet it is used to wash your dishes. Can we be certain that no residues are left on your crockery to be picked up by your food?

Furniture polish

Commonly contain nitrobenzene, which is highly toxic and easily absorbed throughrepparttar 110102 skin. Petroleum distillates may also be present, which are highly flammable and have been linked to skin & lung cancer.

Laundry products.

These present a veritable cocktail of chemicals, including ammonia, phosphourous, naphthalene & phenol along with numerous others. They can all cause irritation torepparttar 110103 skin, allergies and sinus problems. Any residue left in your clothes can be absorbed into your body throughrepparttar 110104 skin.

Oven cleaner

These arerepparttar 110105 most powerful toxic products that you can introduce into your home. They contain ammonia and other chemicals which can irritaterepparttar 110106 skin, and produce fumes which can attackrepparttar 110107 respiratory system. Any residue left in your oven may be intensified when you next use it.

Toilet cleaner

These usually contain hydrochloric acid which is highly corrosive,repparttar 110108 eyes and skin being particularly vulnerable to attack, and known to be harmful torepparttar 110109 liver and kidneys. If mixed with other chemical products, chlorine can be produced which can be fatal in high concentrations.

The above is a brief overview ofrepparttar 110110 possible risks, and it must be stressed thatrepparttar 110111 effects noted forrepparttar 110112 individual chemicals are for high levels of exposure. However,repparttar 110113 point being made by many agencies such as Greenpeace is thatrepparttar 110114 level of exposure inrepparttar 110115 home is unknown and unmonitored.

What can you do as a householder to minimiserepparttar 110116 risk to yourself and your family? Well, if you are able, you may want to try talking to your grandmother, as past generations have had to undertake most modern cleaning tasks withoutrepparttar 110117 intervention ofrepparttar 110118 chemical industry. For instance, she may have used common salt and baking soda to cleanrepparttar 110119 oven and not risk poisoning anyone.

The easiest way to avoidrepparttar 110120 risk is to avoidrepparttar 110121 products. Governments are not going to outlawrepparttar 110122 chemicals, andrepparttar 110123 manufacturers are not going to replace them unless they are forced to do so, either by regulation or by consumer pressure.

There are a growing number of manufacturers who are producing safe products based on natural ingredients that do not presentrepparttar 110124 same threats asrepparttar 110125 more established and heavily promoted products.

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