Posted on 09/08/2002 4:53:30 PM PDT by 2sheep
Small tsunami hits PNG after powerful quake
"PORT MORESBY, Sept 9 (Reuters) - A powerful 7.6 magnitude earthquake struck northern Papua New Guinea on Monday, knocking coastal homes off their stilts, generating a small tsunami and killing three people, according to initial reports.
The quake hit near an area of the poor South Pacific nation where one of a similar size triggered tsunamis that killed more than 2,000 people in 1998. This time, a one to two metre (3.3-6.7 ft) wave swept ashore but caused no damage, officials said ...
The quake was close to the coastal town of Aitape where more than 2,000 people were killed in July 1998 when 15-metre (50 ft) waves swept 500 metres (550 yards) inshore.
The Aitape quake measured 7.1, too small to have caused the tsunamis. Some experts say the quake may have triggered a submarine landslide that sent the huge waves roaring inland."
I thought I had it bad being 60 kilometers from the San Andreas Fault! ;^)
Try www.mapzone.co.nz to see where I'm talking about.
How do we know that this was the top end of the quake? I was once in the midst of an earthquake swarm not far from a volcanic mountain. The geologists called and were very interested in what was going on. I asked, "How do you know if this is a swarm building up to a big blow or quake or just a swarm cooling down from one already passed?"
They said. "We don't know. We can only tell by looking back after the biggest event."
If a swarm predates a big blow (like Mt. St. Helens did and like the various swarms around the world), then you can't tell if a swarm of varying sizes (say 3.7, 4.2, 3.6, 4.0, 3.9, 4.5, 4.6) or as in this instance 7.6, 4.9, 5.1, 5.0, 5.0, 5.0, 5.1 is getting bigger or getting smaller. In other words, the 7.6 might not have been the top end.
Here is a book which indicates that accurate forecasts can be made in the scientific community. Volcano Eruption Great Earthquakes Advance Warning Techniques Book
The main shock was 2 1/2 orders of magnitude bigger than the significant aftershocks. This means you can add up all the energy released in the aftershocks, and it still wouldn't compare to the energy relase in the main quake. Aftershocks are a sort of like the Earth trying to settle back in to its old routine.
Would you explain what you mean, please? See this link (click here). Wouldn't the subduction in PNG aggravate the already hot volcanoes in that area? When the Pacific plate subducts under Mt. St. Helens and Mt. Hood, it would heat up points in the cascades, therefore, how is this a different class? The whole Pacific Rim seems to be rattling like a pressure cooker and after the 7.6 and 7.7 in Fiji on August 19, volcanoes acted up in Hawaii and Japan, so it looks like there might be a relationship between the quakes and volcanoes.
Cross-section of the subduction zone below New Britain. From Johnson (1976).
"A collapsed volcano in the Eastern Sierra near Mammoth Lakes has been generating anxiety-provoking seismic swarms for decades, if not centuries, and geologists have speculated widely about the underground processes causing these quakes.
Now, a Berkeley seismologist has discovered evidence that some of these earthquakes are being caused by locked, water-saturated faults cracking open several miles underground, shoved apart by sudden increases in fluid pressure.
Based on his analysis of seismic data from quakes in the volcanic crater, Assistant Professor of Geophysics Douglas Dreger concludes that magma moving through large cracks periodically encounters fractures saturated by water. The magma heats them so suddenly that the expanding water, steam or bubbles drive the rocks apart as much as four inches in a matter of seconds.
The sudden expansion triggers an earthquake.
'As the fluid is heated, it pressurizes, reducing the frictional stress along the fault and allowing the fault to move, generating an earthquake,' said Dreger. 'As the pressurization continues, you may have continued deformation, but without seismic activity.'"
Compare the magmatic movement model above with the traditional elastic strain theory, using the 1872 Owens Valley quake +/- 8.3 as an example:
Faults and earthquakes are the result of deep-seated forces, called tectonic stress, which gradually deform the rocks of the earth's crust until rupture occurs. The rock deformation, called strain, is largely elastic and is stored in the rocks as elastic strain energy. When the strength of the rock is exceeded, rupture occurs, usually along faults which are zones of weakness. The rocks on opposite sides of the fault slide past each other as the rocks spring back to a relaxed position. The strain energy is released partly as heat and partly as elastic waves called seismic waves. The passage of these seismic waves produces the ground-shaking of an earthquake.
Since 1850 there have been three great earthquakes (M 8 or greater) in California. Both the Fort Tejon earthquake of 1857 and the famous San Francisco earthquake of 1906 resulted from movement along the San Andreas fault. The Owens Valley earthquake of 1872 was produced by movement along the Owens Valley fault on the east side of the Sierra Nevada Mountains. This great earthquake killed twenty-seven people and damaged or destroyed nearly every building in the towns of Lone Pine and Independence. This earthquake occurred at 2:30 in the morning, and Californians from Red Bluff to San Diego were awakened by the shaking of their beds. The quake produced about 4 feet vertical displacement and up to 18 feet lateral displacement.
When I said "different class" of earthquake, I was referring to the causal mechanisms, rather than the magnitude or intensity of shaking. A third class of seismic event includes meteorite impacts. I hope this helps.
Jer 51:6 Flee out of the midst of Babylon, and deliver every man his soul: be not cut off in her iniquity; for this is the time of the LORD'S vengeance; he will render unto her a recompence.
This has been fairly thoroughly discussed on the two threads below, so I won't repeat that here, except to say there are many dreams, visions and prophecies of a heap of trouble for the "midst" of Babylon (New Madrid) because Pres. Bush has entertained Islamic priests in the White House and still wants to divide Israel by placing an abomination called a Palestinian state in the middle of it.
Short story: Sow trouble in the middle of another nation, reap trouble in the middle of your own. America divided and a 9+ quake causes the west coast to fall into the sea or at least go under a lot of water. I won't argue with Tim Snodgrass' dream or vision of that occurring, just his interpretation which I think is too soft. There should be a whole lot of repenting going on and there isn't.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.