|
Confirmed User
Industry Role:
Join Date: Feb 2002
Location: NYC, NY
Posts: 8,531
|
Tsunamis and the Jersey Shoreline and surrounding regions
Mega-Tsunamis are a true threat to the New Jersey coastline. It will cause total chaos due to the extreme high population density in the state and surroundings such as New York City and Philadelphia, although Philadelphia is approximately 50 miles away from the shoreline, a potential and very likely mega tsunami wave of 200 to 500 feet will easily wash across the low lying plain of central and south jersey and well into eastern Pensylvania. However, northwest jersey is a little bit safer due to higher elevations of the Kittany Mountains, but the major urban areas in north Jersey such as Newark, Paterson, and Jersey City are very vunerable and can easily be heavily damaged by these mega-tsunamis because of their low elevations This also includes New York city and all of Long Island.
This speculation should be tempered, perhaps, by a reading (1602-3) in 1939, in which Cayce was asked, "Is Atlantis rising now?" The answer was that "In 1998 [emphasis added] we may find a great deal of the activities as have been wrought by the gradual changes that are coming about "....[and that]...."this [Atlantis rising] is a gradual, not a cataclysmic activity in the experience of the Earth in this period."
A large and very unstable mass of land off of North Africa will sometime soon collapse due to a volcano eruption causing an enourmous underwater landslide that will displace a termendous amout of water moving at 500 miles per hour toward the US east coast with several waves rolling up to a range from 200 to 500 feet high. And the New Jersey coastline is definetely no exception to this great devasting mega-tsunami. It will cause extreme havoc because New Jersey's very dense population. Not only does New Jersey have plenty of major urban areas, also there are many overcrowding suburban areas especially in Central Jersey, where the elevation is low, which will cause that area to easily mowed over by these mega-tsunamis. When the estimated 500-foot wave strikes the Jersey shore it will demolish those cities on the immediate coast that are heavily populated, such as Atlantic City, Wildwood, Seaside Heights, Asbury Park, Belmar and Long Branch. As the wave continues to move west it will decrease in size but will take a long westward to distance to finally stop. Cities and towns in New Jersey that would be next in line to be flattened would be places such as Red Bank and Howell which are only about 40 feet above sea level and heavily populated. By that time the mega-tsunami wave should only be decreased to about 250 feet high and still has a long way westward to go until it stops. Other cities and towns that are included in that area would be Freehold, Old Bridge, and New Brunswick. "Hundreds of thousands of homes and buildings would be destroyed, this would be terrible with millions drowning in a wave that will still be over 200 feet high," says CNN reporter, Rodger Barry. By that time, not only is Monmouth, Ocean, Atlantic, and Cape May counties under the gun, northern Jersey's urban areas will be slammed by this wave. It is estimated that wave will still be in the range of 200 to 300 feet high while plowing through cities such as Newark, Elizabeth, Jersey City, Hoboken, Paterson, and even Paramus. Not to forget all of New York City in which the wave could be worse there considering New York City is east of New Jersey putting closer to the Atlantic Ocean. By the time the wave reaches the Delaware River which is the complete opposite side of New Jersey, it should finally be decrease to 20 feet tall, but that is still as big as the waves of the tsunamis that hit Southeast Asia this past December. Therefore the damage in places such as Trenton, Camden, and even the eastern areas of Philadelphia should be compareable to the damage that was caused in the southeastern Asian countries. This waves is expected to finally stop moving by the time it crosses into Pennsylvania, around the King of Prussia area.
If we switch to California for a moment, note that tsunami waves originating from the giant (M9.5) earthquake in Chile in 1960, produced some damage to yachts and coastal engineering works in both San Diego and Los Angeles harbors, even though the waves traveled diagonally through shallow water for hundreds of miles. Both of these harbors face south, and thus the waves had a more direct approach.
"The amplitude of the waves coming into San Diego reached at least 5 ft and continued to be measurable for the entire day with considerable variation in heights. Strong currents moved up the entrance of both harbors and caused ships to break their lines and crash into the pier pilings." (Shepard, F.P., and Others, 1963, Submarine Geology, Harper & Row, New York).
The U.S. Mid-Atlantic "Surprise Tsunami" Hazard
Giant waves emanating from the Cumbre Vieja volcano in the Canary Islands is not the hazard it seems when compared to the possibility of a surprise tsunami generated off Virginia's coast. Coastal communities around the North Atlantic basin will have fair warning of any Canary Island tsunami waves by paying attention to geophysical monitoring services that track eruptions and potential landslides.
But for U. S. mid-Atlantic communities there is the possibility for surprise tsunamis that may be generated locally and without warning. As presented at the beginning of this article, sediments along the outer continental margin are so soggy and gas charged that they can slump spontaneously. Marine geologists identified fresh slump scars last year off New Jersey, and Driscoll, and others, recently found a 25-mile-long system of cracks along the shelf edge off southern Virginia. These cracks lie just north of the approximately 16,000-year-old (Albemarle) submarine landslide.
Should an Albemarle-like slide occur tomorrow off Virginia, how big might the tsunami waves be? Steven Ward (Univ. Calif. at Santa Cruz) has modeled the case of a hypothetical slide moving down Norfolk Canyon, whose headwall is around 62 miles due east of Virginia Beach. He traced the edge of the Albemarle debris field and transported the outline northward so that the head scarp overlies the newly found shelf-edge cracks. Using data for slump speeds and volumes inferred from studies of former slides, Ward's model was able to simulate the sea-surface disturbance for the hypothetical Norfolk Canyon slide. The slide would run out to a point about 140 miles from shore.
Thirty minutes after the slide began, peak waves 32 feet high would be generated. Deep ocean water to the east would allow the waves to travel at speeds of around 375 miles per hour. But to the west, shallows barely 165 feet deep keep the waves to a comparative crawl (about 50 mph). After two hours, waves reach Virginia Beach. Ward concluded that although waves along the shore from North Carolina to Long Island would vary from 13 to 23 ft in amplitude, most visitors to this stretch of the shoreline would experience only a very few peak waves of 6 to 13 ft.
A tsunami wave striking Virginia Beach would most likely appear as flooding. If its amplitude were 20 ft that means that the height of the flooding would be 20 ft above local mean water level at the time. If the trough of the wave arrives first, the water level will drop rapidly to minus 20 ft, exposing the bottom. This may be the only warning to residents that a large tsunami is approaching and it may move so quickly that people who wandered out on the bottom could be drowned. Although there may be an interval of minutes - to perhaps an hour - between the arrival of flooding waves, the second, third, or later waves can be more destructive than the first.
Tsunami-wave run-up distance and damage to structures depends upon a variety of factors such as the angle of slope of the beach, tide height, and building-construction. While Ward's wave amplitudes, if realized, would be somewhat less damaging than those expected from a Cumbre Vieja slide, tsunami waves' ability to surprise is the greatest danger. A two-hour warning for a Norfolk Canyon slide would not be enough for most people to get out of harms way, even if seismic detection of the slide could somehow be broadcast quickly. And what if the slide occurred at midnight? How many would hear the broadcast?
Unlike the U.S. Pacific rim, the U.S. east coast has no tsunami-warning system in place. It is time for NOAA to install a tsunami-detection system on Virginia's continental shelf, such as it has done in the Gulf of Alaska, and off Oregon and Washington. Data on tsunami waves could then be sent in real-time to mid-Atlantic coastal communities. It would then be up to each community to warn vulnerable residents via strategically placed sirens, as is done now in Hawaii.
|