02 03 04

Sabtu, 31 Maret 2012

Abiotic Oil: Science or Politics?


Abiotic Oil: Science or Politics?
By Ugo Bardi

[Ugo Bardi is professor of Chemistry at the University of Florence, Italy. He is also member of the ASPO (Association for the study of peak oil). He is the author of the book "La Fine del Petrolio" (the end of oil) and of several studies on oil depletion.
Ugo Bardi offers a simple assessment of the abiotic theory. His logic is so clear, and the culmination of his argument is so cogent, that even a child could understand it. And the conclusion is inescapable - at least to honest enquiry - abiotic theory is false, or at best irrelevant. -DAP]

OCTOBER 4, 2004: 1300 PDT (FTW) -- For the past century or so, the biological origin of oil seemed to be the accepted norm. However, there remained a small group of critics who pushed the idea that, instead, oil is generated from inorganic matter within the earth's mantle.
The question might have remained within the limits of a specialized debate among geologists, as it has been until not long ago. However, the recent supply problems have pushed crude oil to the center stage of international news. This interest has sparked a heated debate on the concept of the "production peak" of crude oil. According to the calculations of several experts, oil production may reach a maximum within a few years and start a gradual decline afterwards.
The concept of "oil peak" is strictly linked to a view that sees oil as a finite resource. Several economists have never accepted this view, arguing that resource availability is determined by price and not by physical factors. Recently, others have been arguing a more extreme view: that oil is not even physically limited. According to some versions of the abiotic oil theory, oil is continuously created in the Earth's mantle in such amounts that the very concept of "depletion" is to be abandoned and, by consequence, that there will never be an "oil peak."
The debate has become highly politicized and has spilled over from geology journals to the mainstream press and to the fora and mailing lists on the internet. The proponents of the abiotic oil theory are often very aggressive in their arguments. Some of them go so far as to accuse those who claim that oil production is going to peak of pursuing a hidden political agenda designed to provide Bush with a convenient excuse for invading Iraq and the whole Middle East.

Normally, the discussion of abiotic oil oscillates between the scientifically arcane and the politically nasty. Even supposing that the political nastiness can be detected and removed, there remains the problem that the average non-specialist in petroleum geology can't hope to wade through the arcane scientific details of the theory (isotopic ratios, biomarkers, sedimentary layers and all that) without getting lost.
Here, I will try to discuss the origin of oil without going into these details. I will do this by taking a more general approach. Supposing that the abiogenic theory is right, then what are the consequences for us and for the whole biosphere? If we find that the consequences do not correspond to what we see, then we can safely drop the abiotic theory without the need of worrying about having to take a course in advanced geology. We may also find that the consequences are so small as to be irrelevant; in this case also we needn't worry about arcane geological details.

In order to discuss this point, the first task is to be clear about what we are discussing. There are, really, two versions of the abiotic oil theory, the "weak" and the "strong":
- The "weak" abiotic oil theory: oil is abiotically formed, but at rates not higher than those that petroleum geologists assume for oil formation according to the conventional theory. (This version has little or no political consequences).
- The "strong" abiotic theory: oil is formed at a speed sufficient to replace the oil reservoirs as we deplete them, that is, at a rate something like 10,000 times faster than known in petroleum geology. (This one has strong political implications).
Both versions state that petroleum is formed from the reaction of carbonates with iron oxide and water in the region called "mantle," deep in the Earth. Furthermore, it is assumed (see Gold's 1993 paper) that the mantle is such a huge reservoir that the amount of reactants consumed in the reaction hasn't depleted it over a few billion years (this is not unreasonable, since the mantle is indeed huge).
Now, the main consequence of this mechanism is that it promises a large amount of hydrocarbons that seep out to the surface from the mantle. Eventually, these hydrocarbons would be metabolized by bacteria and transformed into CO2. This would have an effect on the temperature of the atmosphere, which is strongly affected by the amount of carbon dioxide (CO2) in it. The concentration of carbon dioxide in the atmosphere is regulated by at least two biological cycles; the photosynthetic cycle and the silicate weathering cycle. Both these cycles have a built-in negative feedback which keeps (in the long run) the CO2 within concentrations such that the right range of temperatures for living creatures is maintained (this is the Gaia model).
The abiotic oil-if it existed in large amounts-would wreak havoc with these cycles. In the "weak" abiotic oil version, it may just be that the amount of carbon that seeps out from the mantle is small enough for the biological cycles to cope and still maintain control over the CO2 concentration. However, in the "strong" version, this is unthinkable. Over billions of years of seepage in the amounts considered, we would be swimming in oil, drowned in oil.
Indeed, it seems that the serious proponents of the abiotic theory all go for the "weak" version. Gold, for instance, never says in his 1993 paper that oil wells are supposed to replenish themselves.1 As a theory, the weak abiotic one still fails to explain a lot of phenomena, principally (and, I think, terminally): how is it that oil deposits are almost always associated to anoxic periods of high biological sedimentation rate? However, the theory is not completely unthinkable.

At this point, we can arrive at a conclusion. What is the relevance of the abiotic theory in practice? The answer is "none." The "strong" version is false, so it is irrelevant by definition. The "weak" version, instead, would be irrelevant in practice, even if it were true. It would change a number of chapters of geology textbooks, but it would have no effect on the impending oil peak.
To be sure, Gold and others argue that even the weak version has consequences on petroleum prospecting and extraction. Drilling deeper and drilling in areas where people don't usually drill, Gold says, you have a chance to find oil and gas. This is a very, very weak position for two reasons.
First, digging is more expensive the deeper you go, and in practice it is nearly impossible to dig a commercial well deeper than the depth to which wells are drilled nowadays, that is, more than 10 km.
Secondly, petroleum geology is an empirical field which has evolved largely by trial and error. Petroleum geologists have learned the hard way where to drill (and where not to drill); in the process they have developed a theoretical model that WORKS. It is somewhat difficult to believe that generations of smart petroleum geologists missed huge amounts of oil. Gold tried to demonstrate just that, and all that he managed to do was to recover 80 barrels of oil in total, oil that was later shown to be most likely the result of contamination of the drilling mud. Nothing prevents others from trying again, but so far the results are not encouraging.

So, the abiotic oil theory is irrelevant to the debate about peak oil and it would not be worth discussing were it not for its political aspects. If people start with the intention of demonstrating that the concept of "peak oil" was created by a "Zionist conspiracy" or something like that, anything goes. In this case, however, the debate is no longer a scientific one. Fortunately, as Colin Campbell said, "Oil is ultimately controlled by events in the geological past which are immune to politics."


1 Thomas Gold, of Cornell University, has been one of the leading proponents of the abiotic oil theory in the West. The theory, actually, had its origin in the work of a group of Ukrainian and Russian scientists.

Source: http://www.aspoitalia.net

Rabu, 21 Maret 2012

Fossils From Animals And Plants Are Not Necessary For Crude Oil And Natural Gas, Swedish Researchers Find


Fossils From Animals And Plants Are Not Necessary For Crude Oil And Natural Gas, Swedish Researchers Find

What would happen if it were proven that "fossil fuels" weren't the result of decaying plant and animal matter, were actually created within the Earth due to simple chemistry and you could not be scared into believing that we were "running out" of oil and natural gas?
Estimates of how much crude oil we have extracted from the planet vary wildly. As late as May of 2009 a report published in the International Journal of Oil, Gas and Coal Technology suggested that we may have used more than we think.
The idea that we are running out of oil is not a new one. Scientists have told us that oil is a limited resource which was formed millions of years ago by the decaying vegetation and biomass of extinct species of plants and animals. With an estimated 1- trillion barrels of oil already extracted from deep wells since commercial drilling began around 1870, many predict that we are nearing the mid-point of remaining oil on the planet.
But there have always been those who claim that oil is a natural substance that forms automatically in the Earth's mantle. They say that it is virtually everywhere, if you can drill deep enough to tap it.
Proponents of so-called "abiotic oil" claim that the proof is found in the fact that many capped wells, which were formerly dry of oil, are found to be plentiful again after many years, They claim that the replenished oil is manufactured by natural forces in the Earth's mantle.
Critics of the abiotic theory disagree. They claim that capped wells may appear to refill after a few years, but they are not regenerating. It is simply an effect of oil slowly migrating through pore spaces from areas of high pressure to the low-pressure area of the drill hole. If this oil is drawn out, it will take even longer for the hole to refill again. They hold that oil is a non-renewable resource generated and deposited under special biological and geological conditions.
Until now these believers in "abiotic oil" have been dismissed as professing "bad science" but -- alas -- a new study has proven them correct!
Reported in ScienceDaily, researchers at the Royal Institute of Technology (KTH) in Stockholm have managed to prove that fossils from animals and plants are not necessary for crude oil and natural gas to be generated. The findings are revolutionary since this means, on the one hand, that it will be much easier to find these sources of energy and, on the other hand, that they can be found all over the globe.
"Using our research we can even say where oil could be found in Sweden," says Vladimir Kutcherov, a professor at the Division of Energy Technology at KTH.
Together with two research colleagues, Vladimir Kutcherov has simulated the process involving pressure and heat that occurs naturally in the inner layers of the earth, the process that generates hydrocarbon, the primary component in oil and natural gas.
According to Vladimir Kutcherov, the findings are a clear indication that the oil supply is not about to end, which researchers and experts in the field have long feared.


Abiotic Oil

 
The abiotic oil formation theory suggests that crude oil is the result of naturally occurring and possibly ongoing geological processes. This theory was developed in the Soviet Union during the Cold War, as the Union needed to be self sufficient in terms of producing its own energy. The science behind the theory is sound and is based on experimental evidence in both the laboratory and in the field. This theory has helped to identify and therefore develop large numbers of gas and oil deposits. Examples of such fields are the South Khylchuyu field and the controversial Sakhalin II field.
In its simplest form, the theory is that carbon present in the magma beneath the crust reacts with hydrogen to form methane as well as a raft of other mainly alkane hydrocarbons. The reactions are more complicated than this, with several intermediate stages. Particular mineral rocks such as granite and other silicon based rocks act as catalysts, which speed up the reaction without actually becoming involved or consumed in the process.
Experiments have shown that under extreme conditions of heat and pressure it is possible to convert iron oxide, calcium carbonate and water into methane, with hydrocarbons containing up to 10 carbon atoms being produced by Russian scientists last century and confirmed in recent US experiments. The absence of large quantities of free gaseous oxygen in the magma prevents the hydrocarbons from burning and therefore forming the lower energy state molecule carbon dioxide. The conditions present in the Earth's mantle would easily be sufficient for these small hydrocarbon chains to polymerise into the longer chain molecules found in crude oil.

Vladimir Kutcherov adds that there is no way that fossil oil, with the help of gravity or other forces, could have seeped down to a depth of 10.5 kilometers in the state of Texas, for example, which is rich in oil deposits. As Vladimir Kutcherov sees it, this is further proof, alongside his own research findings, of the genesis of these energy sources -- that they can be created in other ways than via fossils. This has long been a matter of lively discussion among scientists.
"There is no doubt that our research proves that crude oil and natural gas are generated without the involvement of fossils. All types of bedrock can serve as reservoirs of oil," says Vladimir Kutcherov, who adds that this is true of land areas that have not yet been prospected for these energy sources.
But the discovery has more benefits. The degree of accuracy in finding oil is enhanced dramatically -- from 20 to 70 percent. Since drilling for oil and natural gas is a very expensive process, the cost picture will be radically altered for petroleum companies, and in the end probably for consumers as well.
"The savings will be in the many billions," says Vladimir Kutcherov.
To identify where it is worthwhile to drill for natural gas and oil, Vladimir Kutcherov has used his research to arrive at a new method. It involves dividing the globe into a finely meshed grid. The grid corresponds to fissures, so-called 'migration channels,' through underlying layers under the surface of the earth. Wherever these fissures meet, it is suitable to drill.
According to Vladimir Kutcherov, these research findings are extremely important, not least as 61 percent of the world's energy consumption derives from crude oil and natural gas.
The next step in this research work will involve more experiments, but above all refining the method will make it easier to find places where it is suitable to drill for oil and natural gas.
Vladimir Kutcherov, Anton Kolesnikov, and Alexander Goncharov's research work was recently published in the scientific journal Nature Geoscience.

Bibliography:
1. Geophysical Laboratory, Carnegie Institution of Washington, Washington, District of Columbia 20015, USA
2. Lomonosov Moscow State Academy of Fine Chemical Technology, 117571 Moscow, Russia
3. Royal Institute of Technology, SE-100 44 Stockholm, Sweden

Source: http://viewzone.com/abioticoilx.html

Senin, 19 Maret 2012

Highest and Lowest Points on Mars


Highest and Lowest Points on Mars
A volcano is the tallest mountain - An asteroid crater is the deepest basin

Spectacular events determined the highest and lowest elevation points on Mars. The lowest point was blasted by an enormous asteroid impact which formed the Hellas Impact Crater. The highest point was built by repeated eruptions of Olympus Mons, the largest volcano in our solar system. Although Mars is a smaller planet than Earth, the heights and depths of these features are enormous in comparison.

Topographic Map of Mars


The image above is a colorized topographic map of Mars. This Mercator projection map shows low elevations as a deep blue color and high elevations as a white color (see elevation scale below). The map was prepared by NASA and is based on data from the Mars Orbiter Laser Altimeter, an instrument on the Mars Global Surveyor spacecraft. The highest point on Mars is the Olympus Mons Volcano (marked by a flag with the letter "H"). The peak of Olympus Mons is 21,229 meters (69,649 feet) above the Mars areoid (a reference datum similar to Earth's sea level). The lowest point is within the Hellas Impact Crater (marked by a flag with the letter "L"). The lowest point in the Hellas Impact Crater is 8,200 meters (26,902 feet) below the Mars areoid. Detail maps of Olympus Mons Volcano and the Hellas Impact Crater are shown below

  

"Sea Level" on Mars?
On Earth we use "sea level" as a reference datum. The elevation of mountains are given in feet above sea level and the depths of the ocean are expressed in feet below sea level. On Mars there is no sea level to serve as a reference. Instead a substitute datum is use. This datum is known as the Mars areoid.

The Mars areoid represents an equipotential surface of the Goddard Mars Gravity Model. The Mars areoid is an imaginary sphere with a center that coincides with the center of Mars and a radius of 3,396,000 meters. We can think of it as a reference elevation, similar to the zero elevation on Earth being mean sea level. (The radius used for the Mars areoid is very close to the average radius of Mars along its equator. That value is 3,396,196 meters.)

To create the Mars topographic map, data from the Mars Orbiter Laser Altimeter as used to calculate the radius of Mars at millions of observation points across surface of the planet. Martian elevation values were obtained by subtracting the radius of the Mars areoid from the radius of Mars at each observation point. The resulting elevations were used to produce the topographic map.

Olympus Mons Volcano - Highest Point on Mars


Olympus Mons volcano is the highest point on Mars at an elevation of 21,229 meters (69,649 feet) above the Mars areoid (a reference datum similar to Earth's sea level). It is also the highest mountain in the solar system and the solar system's largest volcano. In this image, Olympus Mons is the largest volcano. Lava flows from Olympus Mons and its neighboring volcanoes have resurfaced the planet in this area. These lava flows are not heavily cratered, revealing that the eruptions which formed them occurred at a point in the planet's history that was after the heavy asteroid bombardment. NASA Image.

Oblique view of Olympus Mons from the Mars Global Surveyor Mission

Vertical image of Olympus Mons from the Viking Orbiter Mission.

More About Olympus Mons
Olympus Mons is an enormous volcano. It stands about 25 kilometers (15.5 miles) higher than its surrounding landscape and it is over 500 kilometers (310 miles) in width. The map above has been enhanced to make topographic features more obvious. On that map, Olympus Mons looks steeper than it actually is.

Olympus Mons is a gently sloping shield volcano, much like the volcanoes that make up the Hawaiian Islands. If you were placed on the flank of Olympus Mons and not told that you were standing on the slope of the volcano, you could probably look around and think that you were standing on a gently sloping plain. You would see a gentle slope upwards in one direction and a gentle slope down in the opposite direction.

If you were placed on the rim of the summit crater and looked down the slope of the volcano, your horizon would be located on the volcano's flank. The volcano is that gently sloping and that immense.

Astrogeologists believe that plate tectonics processes on Mars are no longer active. Olympus Mons is thought to be located on a stationary "plate" over a deep hotspot. The stationary nature of the plate has kept the Olympus Mons fixed above the hotspot, allowing repeated eruptions to build it to a very great height.

In the vertical image from the Viking Orbiter Mission above a sharp change in slope can be seen as a light area that almost completely surrounds the volcano. This light area marks a steep cliff or escarpment about one to four kilometers in height. The origin of this escarpment is debated but remains unknown. Ideas of it being a product of faulting, erosion, landsliding and uplift have all been proposed.

Hellas Impact Crater - Lowest Point on Mars

Hellas Impact Crater (also known as Hellas Planitia) is an enormous impact crater in the southern hemisphere of Mars. It is about 2,300 kilometers (1,400 miles) in diameter and about 9 kilometers (5 miles) deep. It is the largest impact crater on the planet. NASA Image.

Hellas Impact Crater

Although the Hellas Impact Crater usually receives all of the credit for being the lowest point on Mars, the honor actually should go to a younger and much smaller impact crater located deep within the Hellas Impact Crater. It is marked in the image above by a red flag. The asteroid that produced this crater blasted through the floor of the Hellas Crater to produce the lowest elevation on Mars. NASA Image.

Sumber: http://geology.com/articles/highest-point-on-mars.shtml.

Jumat, 02 Maret 2012

The Most Powerful Volcanic Eruption of the 20th Century


The Most Powerful Volcanic Eruption of the 20th Century




The morning of June 6th arrived on the Alaska peninsula to find the area which is now Katmai National Monument being shaken by numerous strong, shallow earthquakes. The most powerful volcanic eruption of the 20th Century was about to begin – but very few people knew about it. The Alaska peninsula has a low population density today but it 1912 it was even lower. Beyond the land shaken by the earthquake activity the beginnings of this event were almost unnoticed.

Location of the 1912 Eruption.
Volcanic Monitoring - 1912 vs. Today
Today the stirring of an important volcano draws enormous global attention. Weeks or even months before most large eruptions a buzz circulates through an electronically-connected community of volcano scientists as clusters of small earthquakes are detected by a global array of seismographs. Many scientists working at diverse global locations interpret this data and begin to collaborate about an awakening volcano and the eruption that might follow. Reports are posted on the internet and news stories communicate the volcano's activity to millions of people. Often it is a false alarm – the volcano is simply stirring.

If the earthquakes strengthen and begin moving upwards, many of these scientists will travel to the area of potential eruption to make observations and set up a local network of data-gathering instruments.
However, in 1912, Alaska was not a US state, very few scientists were supported to do volcanic studies and a worldwide network of seismic monitoring was not in place. Scientists were just starting to understand the mechanics of volcanic eruptions.

Novarupta Volcano Erupts!
On June 6th, 1912 a tremendous blast sent a large cloud of ash skyward and the eruption of the century was underway. People in Juneau, Alaska, about 750 miles from the volcano, heard the sound of the blast – over one hour after it occurred.

For the next 60 hours the eruption sent tall dark columns of tephra and gas high into the atmosphere. By the time the eruption ended the surrounding land was devastated and about 30 cubic kilometers of ejecta blanketed the entire region. This is more ejecta than all of the other historic Alaska eruptions combined. It was also thirty times more than the 1980 eruption of Mount St. Helens and three times more than the 1991 eruption of Mount Pinatubo, the second largest in the 20th Century.

The relative size of the Novarupta eruption compared to others on the basis of cubic miles of magma ejected. USGS Image.
USGS Topographic Map of the Novarupta/Katmai Area Provided by MyTopo.com.

Impact of the Eruption

The inhabitants of Kodiak, Alaska, on Kodiak Island, about 100 miles away, were among the first people to realize the severity of this eruption. The noise from the blast would have commanded their attention and the visual impact of seeing an ash cloud rise quickly to an elevation of 20 miles then drift towards them would have been terrifying.

Within just a few hours after the eruption a thick blanket of ash began falling upon the town - and ash continued falling for the next three days, covering the town up to one foot deep. The residents of Kodiak were forced to take shelter indoors. Many buildings collapsed from the weight of heavy ash on their roofs.
Outside, the ash made breathing difficult, stuck to moist eyes and completely blocked the light of the sun at mid-day. Any animal or person who was caught outside probably died from suffocation, blindness or an inability to find food and water.

Pyroclastic Flow
Back on the peninsula, heavy pyroclastic flows swept over 20 kilometers down the valley of Knife Creek and the upper Ukak River. (A pyroclastic flow is a mixture of superheated gas, dust, and ash that is heavier than the surrounding air and flows down the flank of the volcano with great speed and force.)

These flows completely filled the valley of Knife Creek with ash, converting it from a V-shaped valley into a broad flat plain.

By the time the eruption was over the world’s most extensive historic ignimbrite (solidified pyroclastic flow deposit) would be formed. It covered a surface area of over 120 square kilometers to depths of over 200 meters thick near its source. (The satellite image at right shows the original geographic extent of pyroclastic flow deposits as a yellow line.)

Satellite image of the Novarupta / Katmai area showing the geographic extent of the pyroclastic flow (yellow) and ash deposit contours (red). Image by J. Allen (NASA) using data from University of Maryland’s Global Land Cover Facility. Cartography by B. Cole, Geology.com.

Volcanic Ash
Immediately after the June 6th blast, an ash cloud rose to an elevation of about 20 miles. It was then carried by the wind in a westerly direction, dropping ash as it moved. The ash deposits were thickest near the source of the eruption and decreased in thickness downwind. (The satellite image above/right has red contour lines showing the thickness of the ash deposits in the area of the eruption. Measurable thickness of ash fell hundreds of miles beyond the one meter contour line.)
When the eruption stopped on June 9th, the ash cloud had spread across southern Alaska, most of western Canada and several U.S. states. Winds then carried it across North America. It reached Africa on June 17th.
Although the eruption had these far-reaching effects, most people outside of Alaska did not know that a volcano had erupted. More surprising is that no one knew for sure which of the many volcanoes on the Alaska peninsula was responsible. Most assumed that Mount Katmai had erupted but they were wrong.
 
Valley of Ten Thousand Smokes. Photo taken in 1991 by R. McGimsey, U.S. Geological Survey.


Valley of Ten Thousand Smokes
After the eruption, the National Geographic Society began sending expeditions to Alaska to survey the results of the eruption and to inventory the volcanoes of the Alaskan peninsula. Robert Griggs led four of these expeditions. During his 1916 expedition, Griggs and three others traveled inland to the eruption area. What they found exceeded their imagination.

First, the valley of Knife Creek was now barren, level and filled with a loose, sandy ash which was still hot at depth. Thousands of jets of steam were roaring from the ground. Griggs was so impressed that he called it the “Valley of 10,000 Smokes”.

James Hine, a zoologist on the expedition described the location: “Having reached the summit of Katmai Pass, the Valley of Ten Thousand Smokes spreads out before one with no part of the view obstructed. My first thought was: We have reached the modern inferno. I was horrified, and yet, curiosity to see all at close range captivated me. Although sure that at almost every step I would sink beneath the earth's crust into a chasm intensely hot, I pushed on as soon as I found myself safely over a particularly dangerous-appearing area. I didn't like it, and yet I did.”

 
   
Katmai Caldera & Novarupta Dome 

During the eruption a large amount of magma was drained from magma chambers below. The result was a removal of support from beneath Mount Katmai which is six miles from Novarupta. The top several hundred feet of Katmai - about one cubic mile of material - collapsed into a magma chamber below. This collapse produced a crater about two miles in diameter and over 800 feet deep.

Early investigators assumed that Katmai was responsible for the eruption. This assumption was based upon Katmai being near the center of the impact area, Katmai was visibly reduced in height, and early witness accounts thought that the eruption cloud ascended from the Katmai area. Closer observation was not possible and expeditions into the impact zone would be very difficult to accomplish.

The first scientific investigation to get an up-close look at the eruption area did not occur until 1916 when Robert Griggs found a 2-mile-wide caldera where Mount Katmai once stood. He also found a lava dome at the Novarupta vent. These observations convinced Griggs that Katmai was the source of the eruption.

It was not until the 1950s - over forty years after the eruption - that investigators finally realized that ash and pyroclastic flow thicknesses were greatest in the Novarupta area. This discovery produced a revelation that Novarupta - and not Katmai - was the volcano responsible for the eruption (see satellite image medium resolution, 164 KB or higher resolution, 1330 KB). This is possibly the most important false accusation in the history of volcanic study.

Novarupta was a very high latitude eruption.


Ash fall extent map of Alaska volcanoes. Image from USGS Fact Sheet-075-98


Could Novarupta Erupt Again?


Other large eruptions on the Alaska peninsula are certain to happen in the future. Within the last 4000 years there have been at least seven Novarupta-scale eruptions within 500 miles of where Anchorage is located today. Future activity is expected because the Alaska peninsula is on an active convergent boundary.

These large eruptions will have enormous local and global impact. Local impact will include the lahars, pyroclastic flows, lava flows and ash falls that are expected from a volcanic eruption. These can result in a significant loss of life and financial impact. The activity of these volcanoes is monitored by the United States Geological Survey and others so that eruptions can be predicted and their events mitigated.

Large eruptions of Novarupta's scale at high latitudes can have a significant impact upon global climate. Recent studies have linked high latitude volcanic eruptions with altered surface temperature patterns and low rainfall levels in many parts of the world. The 1912 eruption of Novarupta and other Alaska eruptions volcanoes have been linked with drought and temperature changes in northern Africa.

Another significant impact is the distribution of volcanic ash. The image at right shows the ash fall impact areas for five important volcanic eruptions of the 20th century. Augustine (1976), St. Helens (1980), Redoubt (1990) and Spurr (1992) all produced ash falls of significant regional impact. However, Novarupta's ash fall was far greater than any other Alaska eruption in recorded history and contained a greater volume than all of the Alaska eruptions which have been recorded combined.

One of the most important reasons to monitor volcanic eruptions is the potential danger that they present to commercial air traffic. Jet engines process enormous amounts of air and flying through finely dispersed ash can cause engine failure. Impacting the tiny ash particles at high speed is very similar to sandblasting. This can "frost" the jet's windshield and damage external parts of the plane. Before the danger of flying through finely dispersed ash was appreciated several commercial jets were forced to land after sustaining serious damage while in the air. Eruptions the size of Spurr, Augustine, Redoubt and St. Helens can damage jets flying over 1000 miles away. An eruption the size of Novarupta would ground commercial jet traffic across the North American continent.

 

 People can not prevent this type of eruption. They can assess the potentia
Landsat Image of the Novarupta / Katmai Area - 1990
Higher Resolution - Landsat Tutorial


What Can We Do About It?

People can not prevent this type of eruption. They can assess the potential impact, develop with the possibility of loss in mind, plan a response, educate the public and key decision makers, and monitor the region where it might occur.

The more you know about a natural hazard, the greater your chances of avoiding injury or loss. We are lucky to have this record of the past.

Sumber: http://geology.com/novarupta/