Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Massive tsunami sweeps Atlantic Coast in asteroid impact scenario for March 16, 2880

28.05.2003


If an asteroid crashes into the Earth, it is likely to splash down somewhere in the oceans that cover 70 percent of the planet’s surface. Huge tsunami waves, spreading out from the impact site like the ripples from a rock tossed into a pond, would inundate heavily populated coastal areas. A computer simulation of an asteroid impact tsunami developed by scientists at the University of California, Santa Cruz, shows waves as high as 400 feet sweeping onto the Atlantic Coast of the United States.



The researchers based their simulation on a real asteroid known to be on course for a close encounter with Earth eight centuries from now. Steven Ward, a researcher at the Institute of Geophysics and Planetary Physics at UCSC, and Erik Asphaug, an associate professor of Earth sciences, report their findings in the June issue of the Geophysical Journal International.

March 16, 2880, is the day the asteroid known as 1950 DA, a huge rock two-thirds of a mile in diameter, is due to swing so close to Earth it could slam into the Atlantic Ocean at 38,000 miles per hour. The probability of a direct hit is pretty small, but over the long timescales of Earth’s history, asteroids this size and larger have periodically hammered the planet, sometimes with calamitous effects. The so-called K/T impact, for example, ended the age of the dinosaurs 65 million years ago.


"From a geologic perspective, events like this have happened many times in the past. Asteroids the size of 1950 DA have probably struck the Earth about 600 times since the age of the dinosaurs," Ward said.

Ward and Asphaug’s study is part of a general effort to conduct a rational assessment of asteroid impact hazards. Asphaug, who organized a NASA-sponsored scientific workshop on asteroids last year, noted that asteroid risks are interesting because the probabilities are so small while the potential consequences are enormous. Furthermore, the laws of orbital mechanics make it possible for scientists to predict an impact if they are able to detect the asteroid in advance.

"It’s like knowing the exact time when Mount Shasta will erupt," Asphaug said. "The way to deal with any natural hazard is to improve our knowledge base, so we can turn the kind of human fear that gets played on in the movies into something that we have a handle on."

Although the probability of an impact from 1950 DA is only about 0.3 percent, it is the only asteroid yet detected that scientists cannot entirely dismiss as a threat. A team of scientists led by researchers at NASA’s Jet Propulsion Laboratory reported on the probability of 1950 DA crossing paths with the Earth in the April 5, 2002, issue of the journal Science.

"It’s a low threat, actually a bit lower than the threat of being hit by an as-yet-undiscovered asteroid in the same size range over the same period of time, but it provided a good representative scenario for us to analyze," Asphaug said.

For the simulation, the researchers chose an impact site consistent with the orientation of the Earth at the time of the predicted encounter: in the Atlantic Ocean about 360 miles from the U.S. coast. Ward summarized the results as follows:

The 60,000-megaton blast of the impact vaporizes the asteroid and blows a cavity in the ocean 11 miles across and all the way down to the seafloor, which is about 3 miles deep at that point. The blast even excavates some of the seafloor. Water then rushes back in to fill the cavity, and a ring of waves spreads out in all directions. The impact creates tsunami waves of all frequencies and wavelengths, with a peak wavelength about the same as the diameter of the cavity. Because lower-frequency waves travel faster than waves with higher frequencies, the initial impulse spreads out into a series of waves.

"In the movies they show one big wave, but you actually end up with dozens of waves. The first ones to arrive are pretty small, and they gradually increase in height, arriving at intervals of 3 or 4 minutes," Ward said.

The waves propagate all through the Atlantic Ocean and the Caribbean. The waves decay as they travel, so coastal areas closest to the impact get hit by the largest waves. Two hours after impact, 400-foot waves reach beaches from Cape Cod to Cape Hatteras, and by four hours after impact the entire East Coast has experienced waves at least 200 feet high, Ward said. It takes 8 hours for the waves to reach Europe, where they come ashore at heights of about 30 to 50 feet.

Computer simulations not only give scientists a better handle on the potential hazards of asteroid impacts, they can also help researchers interpret the geologic evidence of past events, Ward said. Geologists have found evidence of past asteroid impact tsunamis in the form of inland sediment deposits and disturbed sediment layers in the seafloor that correlate with craters, meteorite fragments, and other impact evidence. An important feature of Ward’s simulation is that it enabled him to calculate the speed of the water flows created by the tsunami at the bottom of the ocean--more than 3 feet per second out to distances of several hundred miles from the impact.

"That’s like a raging river, so as these waves cross the ocean they’re going to stir up the seafloor, eroding sediments on the slopes of seamounts, and we may be able to identify more places where this has happened," Ward said.

He added that the waves may also destabilize undersea slopes, causing landslides that could trigger secondary tsunamis. Ward has also done computer simulations of tsunamis generated by submarine landslides. He showed, for example, that the collapse of an unstable volcanic slope in the Canary Islands could send a massive tsunami toward the U.S. East Coast.

A tsunami warning system has been established for the Pacific Ocean involving an international effort to evaluate earthquakes for their potential to generate tsunamis. Ward said that asteroid impact tsunamis could also be incorporated into such a system.

"Tsunamis travel fast, but the ocean is very big, so even if a small or moderate-sized asteroid comes out of nowhere you could still have several hours of advance warning before the tsunami reaches land," he said. "We have a pretty good handle on the size of the waves that would be generated if we can estimate the size of the asteroid."

Planetary scientists, meanwhile, are getting a better handle on the risks of asteroid impacts. A NASA-led campaign to detect large asteroids in near-Earth orbits is about half way toward its goal of detecting 90 percent of those larger than 1 kilometer in diameter (the size of 1950 DA) by 2008.

"Until we detect all the big ones and can predict their orbits, we could be struck without warning," said Asphaug. "With the ongoing search campaigns, we’ll probably be able to sound the ’all clear’ by 2030 for 90 percent of the impacts that could trigger a global catastrophe."

Rogue comets visiting the inner solar system for the first time, however, may never be detected very long in advance. Smaller asteroids that can still cause major tsunami damage may also go undetected.

"Those are risks we may just have to live with," Asphaug said.

Tim Stephens | EurekAlert!
Further information:
http://www.ucsc.edu/

More articles from Earth Sciences:

nachricht Sediment from Himalayas may have made 2004 Indian Ocean earthquake more severe
26.05.2017 | Oregon State University

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>