Dora the Explorer's Catastrophic Volcanos and U.S. Earthquakes Page
This page has a general collection of information on catastrophic volcanos worldwide, and catastrophic earthquakes in the U.S. It isn't quite a total compendium; for instance, I have nothing on the threat of one of the Canary Islands collapsing and generating a tsunami to swamp some or all of the American east coast, because, whatever else it is, that threat is very easy to understand. Other threats like those posed by Yellowstone and the Long Valley Caldera are harder to follow.
For geological, seismological, and tectonic terminology, see Dora the Explorer's Earthquake Page
Yellowstone Park is volcanically active. This is what causes the geysers. Under Yellowstone Park is a culdera volcano that blows catastrophically every 600,000 to 700,000 years. It last blew 600,000 years ago, and there has been uplift under the caldera, indicating the buildup of pressure. There is serious controversy about whether that means there is an actual need to attend to this. If it blew, it would wipe out all life in Wyoming and possibly surrounding states, and seriously damage Earth's weather for some years.
A caldera volcano is an especially violent form of volcano. The volcano on Santorini, in the Mediterranean, for instance, is a caldera volcano. They are covered by layers of hard magma and other rock. Over time great pressure builds up under the lava dome. Gas forms - but remains dissolved in teh magma because of the great pressure. If something cracks part of the crust, and especially if water gets into it, which does not happen only in an ocean or sea, magma can escape. Then the pressure lessens, the gas undissolves, and the entire caldera blows sky high, usually in a truly catastrophic volcano, though there are small culdera volcanoes like Mt. St. Helens. The lava dome collapes; leaving a big crater that often becomes a lake. The explosion of Santorini in about 1500 BC caused the plagues of Exodus, and more dramatic tidal waves all over the Mediterranean, catastrophically changed the climate in China for 15 years, left ash in Greenland, and destroyed Cretan civilization. The last volcano as violent as the one under Yellowstone was Mt. Toba, on Sumatra (a hundred miles east of the recent catastrophic earthquake), which caused severe planet wide weather changes and brought the human race to the within about a hundred individuals in East Africa of extinction.
The reason for such a hot spot in Wyoming is a hot spot. A hot spot is a weakened area in the Earth's crust that magma flows through. Hot spots move over time, and Yellowstone's has left a lengthy track of having moved from the border of Oregon. The Hawaian Islands are another well known hot spot. As the hot spot moves, old parts of the island chain erode away and new islands are born. However, the Hawaian volcanoes are among the least explosive volcanoes on earth. It all depends on whether the structure of teh volcano lets magma escape easily, as well as on the type of magma.
BBC/ PBS Horizon Special: Supervolcanoes - Transcript and Web Site Describes supervolcanoes like Krakatoa, Toba and the caldera volcano under Yellowstone Park, which erupts catastrophically every 600,000 to 700,000 years, last erupted 600,000 years ago, is still alive, accounts for the geography and geological activity at Yellowstone Park, and has recently been uplifting.
transcript of the BBC Horizon Supervolcanoes program
Wikipedia article on the Yellowstone Supervolcano
The Snake River Plain and the Yellowstone Hot Spot
Wikpedia article on the Snake River Plain
Yellowstone Volcano Observatory web site Pay attention to the link about a slightly larger earthquake in the park early in 2008 - the page it links to tells us that earthquake activity in the park has been increasing, and also that a flurry of small quakes around the caldera was set off by a major quake in Alaska in 2002.
Volcano Monitoring at Yellowstone National Park
USGS Professional Paper 1717. Integrated Geoscience Studies in the Greater Yellowstone Area—Volcanic, Tectonic, and Hydrothermal Processes in the Yellowstone Geoecosystem. Collection of articles.
Monitoring a Supervolcano in Repose: Article in Elements Journal February 2008
Unusual large number of minor quakes in Yellowstone, end December 2008 Now, that is recent quakes in the Intermountain West, so maybe preserving today's map of recent earthquake activity would be helpful. Don't misinterpret the map as I initially did - the area outlined in red is the caldera, not the earthquake zone! The earthquake zone is shown by the little yellow squares and the big blue squares clumped around the northern end of the lake. The bulge was first noticed around the lake but is actually centered just northwest of the lake and again at the western end of the middle of the caldera. Below is a deformation velocity map showing how much the ground is deforming (bulging) where and in what directions. At its center the bulge bulged upward about 30 inches between the 1920's and the 1970's, according to Bob Smith's repeat of the 1920's geological survey. (I thought the greatest bulge was around the northern end of the lake where recent spate of earthquakes has been in December 2008 but apparently that is wrong.)
For comparison, here is a map of the Yellowstone caldera.
Here is a current (Dec 2008) US News and World Report article about the spate of quakes.
Yahoo news article on the quakes' normalcy:
However, earthquakes over time have not been concentrated over the northern end of the lake. But the Yellowstone observatory does not map the earthquakes over time, only by year. A page of links to those individual yearly mappings of quakes in Yellowstone is here. It looks to me rather like they fluctuate back and forth between the top of the bulge and its sides and edges, and there are several other centers of earthquake activity nearby. The land is not deforming in those areas. however. 2002 was a particularly busy year, but almost half the quakes were in November and December, and apparently a major quake in Alaska set them off.
Yellowstone at a Glance downloadable poster of graphics - viewable online - by University of Utah Seismology and Active Tectonics Research Group very revealing about dynamics of the rise and fall of the land in the area. (suggests cyclic rise and fall of land between caldera and mountain range just north of it), also tracks probable trail of the hot spot eruptions over 16 million years
Neogene Snake River Plain-Yellowstone Volcanic Province - Digital Geology of Idaho, with links to references
Digital Atlas of the Snake River Plain
USGS Yellowstone Volcano Observatory: Volcanic History of the Yellowstone Plateau Volcanic Field
USGS Yellowstone Volcano Observatory Path of the Yellowstone Hotspot
Discovery News: Old Supervolcanoes Give Yellowstone Clues by Larry O'Hanlon
Discovery News: Yellowstone Depths Reveal Rock Plume
Yellowstone's Super Sisters. Includes Toba, Taupo, Valles and Long Valley, and supervolcanoes on Jupiter's moons.
Yellowstone's Plumbing Reveals Plume of Hot and Molten Rock 410 Miles Deep New study finds plume is larger and deeper than previously thought. 20% larger to be precise. It is angled. The most significant piece of evidence, however, is proof that there is a hotspot, which sure expands the plume for those who believed that none existed! Probably they still believe none exists. Related papers find that the magma is cooler than expected, and that the caldera is rapidly refilling, or maybe "recharging".
Yellowstone Plume, Hotspot, and Wasatch Front Earthquake Research University of Utah Tectonics and Active Seismology Research Group papers on Yellowstone Caldera - the papers referenced above.This is only here because it was mentioned in Dinosaur Planet and could confuse people. It may also have been mentioned by Horner in a book about a field or petrified forest of dead dinosaurs. It is an ancient, long dead, volcano. It happened to be one of the earliest ancient supervolcano calderas that was found, or something, and the fact that the distinctive ash from this volcano affected dinosaurs fifty miles away impressed researchers. Actually, there are quite a number of long dead supervolcanoes in the west and midwest; the Rocky Mountain and basin and plain area is actually among other things built on volcanic ground. Long ago it must have been a very interesting place. Researchers are barely sure a caldera is actually there! One other thing - this was the Elkhorn mountain range in Montana, not the harmless Elkhorn mountain in Idaho. Apparently there are eight million geographical features in the west named Elkhorn.
From Little Das' Hunt, Dinosaur Planet. Scott Sampson, Uath Museum of Natural History, "Descovery Quest Paleontologist".
"In a remote corner of Northwestern Montana, scientists unearthed a baffling mystery. The carred bones of dinosaurs. Based on the undisturbed state of the bones, it was concluded that the animals died on the spot. But what killed them?
"...The bones were found among more than 200 petrified trees all found under as much as 6 feet of cinder and ash. In turn, the trees lay within a field of ash covering 9600 sq. mi., one of the largest fields of volcanic ash in the world. Sometime in the late Cretaceous, about 75 million years ago, the forest was destroyed by a powerful volcanic eruption. The trees were leveled by the sheer force of the blast, then buried under a column of ash, along with the dinosaurs. [The Mt. St. Helens eruption in the 1980's produced similar destruction.] Yet the Elkhorn eruption ranks as one of the most powerful ever recorded. By comparison Mt. St. Helens was a mere firecracker".
The storyline is placed when the Rocky Mountains were young volcanic mountains. The Elkhorn Range of Mountains of Montana had rich volcanic soil. The collapse of the Eastern face of the volcanic mountain fueled the blast. The ash plume extended 300 miles from Montana to the inland sea of North America. The dinosaurs the storyline depicts as killed by the pyrochlastic flow lived 50 miles from the eruption.
Roberts, Eric et al, Taphonomy of a petrified forest in the two medicine formation (Campanian), Northwest Montana (This article is available from this source for $15.)
Dixon, Ron, Geology of the Elkhorn Mountains: Volcanics in the Southern Bull Mountain Area
"Approximately 77 million years ago, southwest Montana was the home of an
active volcanic complex. The Elkhorn Mountains Volcanics (EMV), as they are now
known, once contained one of the largest ash-flow volcanic fields on earth. This
volcanic material once covered an estimated 10,400 square miles (26,000
km2) to a depth of
approximately 2.5 miles (4.0 km). By comparison, the Yellowstone National Park
volcanics are estimated to cover only 4,000 square miles (10,000 km2) to a depth of 500 feet (150.0 m).
The EMV are Cretaceous in age "
This Wikipedia article on the Elkhorn Mountains discusses the Elkhorn Mountain Volcanics.
This Wikipedia graphic on late Cretaceous geography will amaze you. Apparently because the sea level was high, most of the central and southeastern United States was covered by water.
Geological posters of historical geological processes of the Western United States
Another large active caldera volcano is located on the eastern edge of the Sierra Nevada mountains, in California, near the Nevada state line. It too is being closely watched, because it is even more active than Yellowstone. It is very similar; with hot springs, rising bulges, and its last catastrophic eruption, which was on a scale similar to Yellowstone's, was about 700,000 years ago. Like Yellowstone it has also erupted more recently and less catastrophically. It is actually a little more dangerous than Yellowstone because it is on active major faults that regularly get moderately strong, 6.0 to 7.5 quakes, that are tied to the San Andreas fault system, and because in addition to uplifting it has been emitting toxic gas which is killing plant life in parts of the caldera. The region the volcano is on is being actively pulled apart by the tectonics of the area, as well as being tied to the San Andreas fault system.
Yellowstone's Super Sisters: Long Valley, California
Wikipedia article on Long Valley Caldera
Geomorphology from Space: Plate T-4: Tectonic history of the southwest
Mammoth Lake Shakes and the Earth Moves. Somewhat speculative but good maps of immediate region, good quake maps of southern California, good quake history of Mammoth Lakes area. Some history of the caldera.
What Shakes Mammoth Lakes? Ron Morris.
Current activity of Mammoth Lakes area by USGS
USGS fact sheet: Living with a restless Caldera -- Long Valley, California (Revised version)
USGS fact sheet: Future Eruptions in California's Long Valley Area -- What's Likely?
Long Valley Caldera and Mono-Inyo Craters Volcanic Field, California
USGS Volcano Hazard Program: Long Valley Observatory web site
Volcanoes of teh World: Long Valley Caldera: Western U.S. - California
The Case of the Missing Moho. September 23, 2004 - the southern Sierra Nevada have lost their boundary between crust and mantle.
Sierra Nevada unmoored - whoops! They not only lost their bottom and are tilting downward toward the west, raising the eastern edge, but they crumpled into the San Andreas fault and they're headed north! (Other versions of that are that the microplate the Sierra Nevada mountains sit on is turning counterclockwise, pulling the lower right quadrant where Long Valley is apart, and compressing the mountains in the other quadrants.)
The North American Tapestry of Time and Terrain: Garlock Fault
Birth of a fault: Connecting the Kern County and Walker Pass, California, earthquakes
Volcanism along the eastern Sierra Nevada frontal scarp
Geologic Provinces of the United States: Basin and Range Province
The Formation of the Rocky Mountains
USGS: Geologic Provinces of the United States: The Rocky Mountain System
Geology 33: Environmental Geomorphology: Major Geomorpo-tectonic Regions
Geo 1002: Earth History. Lecture 38: Tectonics of the Rocky Mountains
The Valles Caldera was a supervolcano, within the past 15 million years; but it is now dead. It is part of a completely failed rift valley in the southwestern United States, that has no apparent tectonic life left in it. The only reason for concern is that the extensional forces pulling the southern central and Western United States apart could conceivably some day reawaken the rift, which would be a ways away from reawakening the caldera.
Jemez, New Mexico. Jemez Volcano Field. Valles Caldera
Yellowstone's Super Sisters: Valles Caldera, New Mexico
Rio Grande Rift GO 568 Structural Geology James S. Aber
Rio Grande Rift, Paul F. Ciesielski, University of Florida
Wikipedia article on La Garita Caldera
It was much larger than Yellowstone, part of a series of eruptions of its kind in the western U.S. 40 to 25 million years ago, and erupted a number of times over a million and a half years.
The Columbia River flood basalt is a key part of the geology of the western U.S., including the Snake River Plain. It was created about 14 million years ago of rift dynamics that apparently are dead.
See discussion at bottom of the page, "Fissure Eruptions". and "Columbia River Flood Basalts"
USGS page on Columbia River Basalts and other northwestern U.S. geological features.
This link appears to suggest a possible relationship between the Columbia River Flood Basalt and the Cascade Subduction Zone, though the flood basalt is supposed to have been created by rifting. Remarkable volcanic dynamics go on behind subduction zones, but that is what the Cascade range is about.
USGS Continental Flood Basalts gives geological and some minerological specifics on the region. Including the Snake River plain. It also discusses similar basalt flood zones elsewhere in North America. I have seen the Columbia River Flood Basalt linked to rifting in Iceland.
Overview of the Geological Provinces of California
USGS Description of the San Andreas Fault
Faults of Southern California main map
Southern California Earthquake data center: Faults of Southern California: Basin and Range Region. Shows teh Owens Valley Fault System as a group of faults northward along teh Sierra Nevada Fault system.
USGS Quaternary Faults and Folds by State and Region Manages to leave off the faults around Mono Lake
USGS Quaternary Faults and Folds Interactive Viewer Using this system, I was able to show that the Owens Valley Fault runs from the Garlock Fault to immediately south of Long Valley, where a linear set of little fault systems pick up and run through Mono Lake. There is also a circular group of faults at the top of the Owens Valey Fault zone called the Volcanic Tablelands faults. The northernmost segment of the Owens VAlley Fault, tha tends at teh Vlocanic Tablelandws, is the Keough Hot Springs section. The next segment is th fault zone that fractured in 1822 - or 1872?
EARTHQUAKE FAQ: UNITED STATES EARTHQUAKES Unusually clear page from UT Austin Institute for Geophysics - they say that California is prone to maximum 8.0 earthquakes, and since these quakes ordinarily occur every 60 to 100 years, and the last one occurred in 1906, another one is about due - or it might not occur for a century.
While the highest probabilities for large tsunamis on the U.S. coast consist of faults and geologically unstable terrain in Alaska, along the coast of the Carolinas, and a volcanic mountain in the Canary Islands, and while the liklihood of a major quake in California is well known, another, possibly bigger problem lies in the Missippi River VAlley in the area of MIssouri and Arkansas. In 1811-1812, a quake of magnitude 7 to 9 occurred near New Madrid, Missouri. The quake caused buildings to collapse and big holes and rifts to open in the earth, caused big tidal waves on the Mississippi river, caused cliffs and bluffs near the river to collapse, temporarily reversed teh flow of the Missippi River, and created a large new lake nearby. The quake caused church bells to ring in Boston, Massachusetts. Recently the area has been seismically active again, with hundreds of quakes up to magnitude 2 a year. There has been concern about the possibilty of another big quake. Today such an event would kill a large number of people and inflict great economic damage.
The greater part of the damage was actually caused by the fact that much of the north central and northeastern U.S. is covered to a great depth by packed rock and sand. The quake caused this stuff to "liquefy" and collapse in many places.
The quake itself was caused by a failed continental rift under that part of the Mississippi River Valley. Shortly before Africa and Europe were separated from the Americas, by the formation of the Atlantic Ocean basin, a seismic rift formed in the Mississippi VAlley, with associated volcanism. Lava flowed from the rifting and formed big hunks of igneous rock along the fault lines. Recently some sort of pressure on the North American continent from both East and West has reactivated the fault zone.
Major quakes have occurred there repeatedly in the past and will occur again though no idea if one will happen any time soon.
Below are some links to information about the fault zone.
Wikipedia article on the New Madrid Earthquake
Wikipedia article on the New Madrid Seismic Zone
TheVirtual Times: The Great New Madrid Earthquake
Southern Illinois University Department of Geology: Earthquakes and the New Madrid Seismic Zone
Rockhounding Arizona: Your Fault, My Fault, and the New Madrid Fault
Source Mechanisms of Earthquakes in the Eastern North America (1976-1996) - a map of large earthquakes in the eastern U.S. in this time period.
Map of earthquakes Recorded in the Eastern U.S. in 1995-98
USGS Areas of Quaternary deformation and liquefaction, New Madrid region, central Mississippi River Valley
USGS Areas of Quaternary deformation and liquefaction in the Mississippi and Ohio Rivers region
USGS Areas of Quaternary and historic liquefaction, coastal North and South Carolina
USGS Seismic hazard map, Conterminous U.S.A. Think the Bush "scientists" got at this page. In theory it still exists but they seem to be too interested in gobbledygooking it to let one get to it. Here is the U.S. Seismic Hazards Map link.
Scientific Probabilities of a major quake in the San Madrid Fault Zone.
New Madrid Seismic Zone: Graphics, Maps, and Information
1812 Madrid earthquake information.
The Mississippi Valley - "Whole Lotta Shakin' Goin' On
Uncovering Hidden Hazards in the Mississippi Valley
Shake Rattle and Roll: The New Madrid Fault Past and Present
NCSA: Shake, Rattle and Roll - about the characteristics of a recent earthquake in Illinois.
Reelfoot Rift (More on the geology of the central United States)
The Cascadia Megathrust and Tectonic Stress in the Pacific Northwest
Pacific Northwest Seismograph Network: FAQS on Pacific Northwest Earthquakes
Cascadia (Pacific Northwest) Seismicity: William P. Leeman, Tsunami!
National Geographic News: Did North American Quake Cause 1700 Japanese Tsunami?
The Earthquake Threat in Southwestern British Columbia John J. Clague Department of Earth Sciences, Simon Fraser University This is a very good review of the research and the various threats that earthquakes in the region pose.
Recent Earthquake Information for Canada
SEISMIC ZONING MAP OF CANADA, 1985: ACCELERATION (NBCC)
Earthquake Zones in Eastern Canada (see Charlevoix Seismic Zone halfway down page, and Lower St. Lawrence seismic zone three-quarters down page)
List of recent Canadian earthquakes
Geocscape Quebec: The Earth Shakes Under Quebec
EARTHQUAKES IN THE CHARLEVOIX-KAMOURASKA SEISMIC ZONE
The Geological Regions of Quebec
See explanation of glacial rebound on page 1.
Reality bytes: Canadian Shield
Cooling and the Laurentian ice sheet
The rocks of the Quebec City area: an entire world beneath our feet
The Teays River (ancient river system that drained northeastern North America)
Canadian Shield, Precambrian Shield or Laurentian Plateau
Geological Provinces of Canada
The Natural Topography of the Great Lakes - St. Lawrence Region
Seismotectonic characteristics of the Lower St. Lawrence Seismic Zone, Quebec: insights from geology, magnetics, gravity, and seismics (abstract). Maurice Lamontagne, Pierre Keating, and Serge Perreault Can. J. Earth Sci./Rev. Can. Sci. Terre 40(2): 317-336 (2003)
The Charlevoix Meteorite Crater
Charlevoix Meteorite Crater - Wikipedia
Superficial Geology from the Hudson Valley to the Massachusetts Coast
The Atlas of Canada: Geological Provinces
Interactive Map of Canadian Shield
A Forest Primeval: A primer on the great forest of the Adirondacks.
The Adirondack Mountains: New Mountains From Old Rocks
Basic Geology and Neotectonics of the Adirondacks
http://www.geo.www.edu/~tsattler/tectonics/adirondack/mountains.html - old link that no longer functions.
A Short Geological History of the Northeastern United States
Geology of the Lake George Region and the Adirondacks
Grenville Event and Virginia geology
Tectonics of the Southern Appalachians
Geologic History of the Appalachian Mountains
The Appalachian Mountains and Plate Tectonics
Geologic Events of the Carolinas and Beyond
The southwestern edge of the ring of fire is so tectonically complex and unstable that it is actually home to more than weekly earthquakes. Sumatra has been home to some doozies. Other catastrophic volcanoes in relatively recent history have occurred in other parts of Indonesia and in the Philippines. The following were all a good deal larger than Mount. St. Helens.
Toba volcano, Sumatra, Indonesia This catastrophic volcano around 75,000 BCE, give or take 10,000 years, is discussed in the Supervolcanos program above. It buried southeast Asia under a layer of ash, caused a severe volcanic winter that may have lasted a thousand years, and helped trigger an ice age. It left a permanent volcanic lake and island in the mountain range on northern Sumatra. This is a recurrent caldera volcano like that at Yellowstone - and scientists do not know if it is done with its cycles of erupting. It brought the human race, previously spread through Asia and Europe, to within a hundred individuals of extinction, which resulted in a serious genetic bottleneck. Humanity should be far more varied and its genetic variation far older than it is - as measured by mitochondrial and Y chromosome DNA, which change between generations only by a slow rate of mutation. The age and degree of genetic variation suggest that 65,000 to 85,000 years ago the worldwide population of humans shrank to between 1,000 and 10,000 reproducing adults. In other words, we came close to preceding Neanderthals into extinction. Though there is archeological evidence that humans lived in Indonesia when the eruption occurred, as evidence of them was buried in the ash, the genetic evidence (of a spread of existing genetic diversity from Africa) and geographical logic (people in Africa were less affected by the eruption and by the resulting catastrophic climate changes) suggests that all of the long term survivors of the eruption whose descendants are living today, were in Africa when the eruption occurred and probably for atleast a thousand years thereafter. Neanderthals were established in Europe and survived there until 35,000 years ago (possibly eliminated by contact and competition with modern humans), but because ice age deserts stood in the way, modern humans did not reach Europe until 45,000 years ago.
Yellowstone's Super Sisters: Toba, Sumatra
This article excerpt explains clearly and concisely what happened. Late Pleistocene human
population bottlenecks, volcanic winter, and differentiation of modern
humans
Note that several popular works by population geneticists claim that there is archeological evidence that arguably shows that some people who were in Indonesia at the time survived the eruption. However, proof that there were people in Indonesia at the time does not couple with proof that the oldest people out of Africa went through Indonesia on their way to Australia, to prove that they are descendants of people who lived in Indonesia when the eruption occurred and survived it. Even mitochondrial DNA analysis of remains that old from Indonesia might not conclusively prove it, but none has been offered.
Tambora - "The Year Without a Summer" 1816 Wikipedia article The Year Without a Summer, also known as the "Poverty Year" and "Eighteen hundred and froze to death" was 1816, in which severe summer climate abnormalities destroyed crops in Northern Europe and the American Northeast. It is now known that the aberrations occured because of the April 5-April 15, 1815 volcanic eruptions of Mount Tambora on the island of Sumbawa in the Dutch East Indies (in today's Indonesia) which ejected over a million and a half tons of dust into the upper atmosphere. As is common following a massive volcanic eruption, temperatures fell on the earth due to reduced sunlight.
Krakatoa and Tambora FAQS from Volcano World by David Elsley
Krakatoa is the modern name of a group of three volcanic islands that exploded violently in 1883, causing an Exodus/ Santorini - like catastrophe throughout southeastern Asia and the western Pacific, and a global year without a summer. Resulting tidal waves were a good deal larger than those of December 26. Ecological catastrophe resulted all over the southwestern Pacific and huge numbers of people and animals who weren't killed immediately died of starvation and disease. The volcano is located in a transtension zone in the strait between Sumatra and Java. A PBS program on Krakatoa showed that the initial problem with Krakatoa was a plug that prevented the escape of magma. Rampino, the volcano expert, figured out that the cause of the most catastrophic explosions was not water seeping into the volcano, which would have made much finer pumice, but the melting of an upper, cooler, level of light colored magma by darker and much hotter magma that followed it in the eruption and mixed with it. This liberated alot of gas, which built up explosive pressure until the volcanic island exploded. A new volcano, Krakatoa Anak, has been building since 1926, growing steadily higher and more violent - though this time nothing was said about a lava plug.
Pinatubo Volcano: The Sleeping Giant Awakens" (1991 eruption - last erupted four centuries earlier.)
Even though it may never happen again, no discussion of catastrophic volcanoes would be complete without mentioning the explosion of Thera/ Santorini in 1680-1520 BCE.
The eruption of Santorini in Greece in 1,650 B.C. was one of the largest (VEI=6) in the last 10,000 years. About 7 cubic miles (30 cubic km) of rhyodacite magma was erupted. The plinian column during the initial phase of the eruption was about 23 miles (36 km) high. The removal of such a large volume of magma caused the volcano to collapse, producing a c aldera. Ash fell over a large area in the eastern Mediterranean and Turkey. The eruption probably caused the end of the Minoan civilization.
Time was 1680-1520. Most likely around 1645-1580. Possibly as early as the end of the Hyksos period, accounting for vague things written about that period. Before end of reign of Tuthmosis III of Egypt. In temple workrooms from Tuthmosis I to III, pumice used that came from this volcano. During reign of Tuthmosis III or the regency of his mother, the Mycenean conquest of Crete occurred. This is demonstrated by a changeover in where what Egytian artifacts are found in relation to what on Crete, and the styles Cretans wear in Egyptian art, temple paintings and that sort of thing. Thera is believed to have exploded about 50 years before Minoan Crete finally fell.
The explosion of Thera/ Santorini destroyed the island of Santorini, which was a main base of trade and possibly the most important center of Minoan civilization. There was ecological devastation and tidal wave devastation on Crete. Minoan civilization was badly weakened and fell to the Myceneans within two generations.
The volcano and the collapse of parts of the culdera, created huge tidal waves around the Mediterranean region, ash fall, darkness, possibly for days, corrupted water, strange animal behavior, animal deaths, disease, and disrupted the weather for years (according to Chinese records from the time). This may be the source of the story of the ten plagues of Egypt, and could also pertain to the story of the drowning of Pharoah's army in the sea. A volcano of that size in that location would also have looked and acted much like the cloud by day and column of fire by night supposed to have led Israelites out of Egypt. Egypt held Palestine from the end of Hyksos rule through the 18th and 19th dynasties, and Pharaoh's armies were stationed all along the coast of Palestine. The 18th dynasty began with chasing the Palestinian and Syrian Hyksos out of Egypt across the Sinai into Palestine. The 19th dynasty ended with Israel in existence, and suffering defeat at the hands of Egypt, and the Philistine invasions. In between, Hapiru and desert bedouins who worshipped Yahweh, led resistance against Egypt from the hills.
As is usually the case with catastrophic volcanoes, Santorini is part of a volcanic island arc behind a subduction fault where several plates are sliding together.
The Eruption of Thera: Devastation in the Mediterranean
BBC: History: The Fall of Minoan Civilization about the work and theories of Floyd McCoy
Nisyros, a similar volcanic caldera, near Santorini This site has a discussion of the plate tectonics that cause the arc of volcanoes, with a map.
The plate major plate boundary that runs through New Zealand twists over on itself between the north and south islands. This contributes to very violent tectonics in the area. The southern part of one of the main islands is expected to fall into the sea one of these days. New Zealand is so tectonically unstable that they find it unsafe to have a proper modern airport. Instead they have a small, primitive airport in the hills.
There was actually a great quake at a point on the fault between New Zealand and Antarctica several days before the Dec. 26 quake in the Indian Ocean.
Three Tectonic Plates Collide Down Under
Breaking up with Gondwanaland. Marine magnatic anomalies on Australia's western margin reveal the true story. Christian Heine. U Of Sidney, Inst of Marine Science.
Taupo Volcano This lake on the North Island in New Zealand was created by the largest volcano in the past 5,000 years - which supposedly no people were immediately around to witness. It created a lake the size of Singapore, and devastated a region the size of the state of New York. It occurred around 130 AD.
Yellowstone's Super Sisters: Taupo, New Zealand
Tectonic Map of western United States
Laramide or Thin-Skinned Tectonics in the Northern Rocky Mountains (this and succeeding two pages)
Geomorphology from Space. See Chapter 2: Tectonic landforms. Includes the southwestern US, southern California, the Cascades, New Mexico, and the Rockies.
This might or might not happen and might or might not inundate some or all of the U.S. In "Megaquake", Discovery channel, April 10, 2005, there was discussion of the fact that successive quakes and water action have cracked the entire side of an elongated volcano on one of the Canary Islands, and that successive quakes and volcanism is likely to cause the side of the mountain to collapse into teh ocean. This mountain has regular collapses of this sort but it might collapse in one piece or piecemeal. If it collapsed in one piece it would generate a monster tsunami that would reach the eastern Atlantic coast. This must have happened repeatedly over time and I've not seen the historical evidence of such catastrophe along the eastern Atlantic Coast. It is unclear whether a tsunami would affect the Carolinas, central America, or every city on the east coast of the U.S.
Another tsunami threat on the east coast is that the coastal shelf off of the Carolinas is unstable.
BBC Science News: Tidal Wave Threat may be over-hyped
Both the end Permian and end Cretaceous events are controversial. The end Permian event was just before the rise of the dinosaurs; it ended teh paleozoic era, and the next stage was the Triassic era of the Mesozoic. There is controversy about whether a monster volcanic eruption or a meterorite impact caused it, and good evidence that both events, which would have occurred during the same period of time, contributed. The earth actually was not exactly geologically nor meteorogically stable throughout the entire Triassic period. The end-Cretaceous or K-T event marks the end of the Mesozoic and the end of the dinosaurs - well, all except modern birds. There is also controversy about whether this was caused by a meteorite impact or an extremely large volcanic eruption, again with good evidence that both probably contributed. The end of the Cretaceous in 65 million BCE was followed by the Cenozoic; the "new age".
The Day the Earth Nearly Died transcript
An alternative theory of the Permian extinction:
Becker's Australia: Impact Deja Vu? A Look Inside the Crater part 1 and Becker's Australia: Impact Deja Vu? A Look Inside the Crater part 2
EXTRATERRESTRIAL CHROMIUM IN THE PERMIAN-TRIASSIC BOUNDARY AT GRAPHITE PEAK, ANTARCTICA. A. Shukolyukov1, G.W. Lugmair1,2, L. Becker3, C. Macisaac1, R. Poreda4. 1Scripps Insti-tution of Oceanography, University of California. Lunar and Planetary Science XXXV (2004)
Earth Science: A Possible End-Permian Impact Crater from Science Week
Disaster down-under: Australian impact craters
Scientific American article not available online; Luann Becker, Repeated Blows, Scientific American, March 2002, 78-83
Science article; Chrondritic Meteor fragments associated with the Permian-triassic boundary in Antarctica Science, 302: 21 November 2003, 1388 - 1392
Fullerenes and Interplanetary dust at the Permian-Triassic boundary Robert J. Poreda and Luann Becker. Astrobiology, 3: Nov 1, 2000.
Deccan Traps Basalt flood eruption in India around 65 million years ago may have helped wipe out the dinosaurs.
The End Cretaceous (K-T) Extinction
Catastrophism and Mass Extinctions Page of links to discussions on causes of the end-cretaceous extinction
BBC Science and Nature: Crater of Death
Wikipedia article: Cretaceous-Tertiary extinction event
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