Pakistan earthquake and its new island

A view of the new island off the coast of Pakistan
from NBC 

A magnitude 7.7-7.8 earthquake hit Pakistan today with an epicenter at about 15 km depth. It was well inside the borders of Pakistan and far from the ocean. Although only a few dozen (46) casualties have been reported as I write this (10:00 p.m. Central Time), the location of the quake is remote and it is likely that casualties will rise, with some estimates being in the thousands  (WAPMERR, The World Agency of Planetary Monitoring and Earthquake Risk Reduction). As this unfolds, an intriguing observation with speculations has hit the news--a mysterious island has risen from the ocean. It is reported to be 20-40 feet high and about 100 feet wide and lies about 350 feet out in the sea from the Gwadar coast (these numbers are very tentative--one report says that it's a mile out to sea, which seems more consistent with the picture that I've included above). It appears to be several hundred miles from the epicenter.
     Residents of Gwadar have reported that an earthquake in 1968 produced an island that remained for about a year before vanishing (but it's reported also to have occurred in the 1940's so I don't know if this is an inconsistency in historical reporting or if it has happened more than once). What could have caused this mysterious phenomenon? Speculation at the moment is our old culprit, liquefaction--the sudden transformation of wet, but solid, sediments to a weak mush upon shaking, just like jiggling quicksand turns it to a mush (for more on liquefaction and the general phenomena discussed here, see my book "The Dynamics of Disaster" to be released by Norton Press on October 21!!). When this happens, structures such as buildings can sink into the ground because it can no longer support their weight.  The liquified material can also squirt up through cracks in the ground forming sand- or mud-volcanoes, and the speculation here is that the island is a big mud volcano.
     This area of the Arabian Sea is known for its mud volcanoes.* Here the oceanic crust of the Arabian Sea is being subducted under Eurasia at a rate of about 4 cm/year.  A sediment pile has been building up on top of this subduction region to a thickness exceeding 6 km, a pile of wet gooey muck. The coastal region is known for mud volcanoes on land, and for the episodic formation of islands of them in the shallow waters off the coast. These are typically destroyed within months. Here's a seismic reflection image of a buried mud volcano from the reference * listed below:

Sometimes these mud islands appear in places that others have appeared before. One, called Malan island, appeared in 1999, unaccompanied by any noticeable earthquake, reoccupying a site of one that had been formed in 1945. It appears to have been driven by methane of bacterial origin.

One of the largest reported mud volcanoes is a complex 100-m high. It has been hanging around since at least 1840 and appears not to have changed much in the intervening decades. Methane of bacterial origin is persistently discharged into its crater mud lake. Eruptions of these gases often show periodicities of several hours that may be related to ocean tides. I'm not sure how the dating is done, but the article * below says that the presence of mud volcano activity in this region can be demonstrated for the last 460,000 years.

*G. Delisle, "The mud volcanoes of Pakistan," Environmental Geology, 46: 1024-1029, 2004.

Super Typhoon Usagi nears Philippines. What is a super typhoon?

Cyclone Usagi on Thursday.
Credit: Colorado State University

Hurricanes Ingrid and Manuel pummel Mexico; Hurricane Humberto in the Atlantic has become a ghost of its former self, and now Super Typhoon Usagi is targeting the Philippines and Taiwan.  It is expected to become merely a severe typhoon when it hits China, right at Hong Kong. Usagi has a diameter of more than 1000 kilometers. It has eclipsed Super Typhoon Utor, which was the strongest storm of the year so far. On Thursday evening, its minimum pressure was very low, 882 mb, which makes it the "deepest and most intense storm to exist on Earth since 1984 (tied with Wilma in 2005)" (quote from The Washington Post). As of Friday at 1:30 p.m. Pacific Time, the eyewall had undergone a replacement and winds have peaked in intensity, but the cyclone is still a very dangerous storm. It will weaken as it hits Taiwan, but is still expected to have winds near 100 mph when it hits Hong Kong (likely on Sunday, right when a major autumn festival is going on).

The past two decades, cyclone activity in the South China Sea has been relatively calm, and there are some forecasters worried that the population may "wrongly think that the typhoon risk in Hong Kong has declined." In 1906 and 1937 typhoons killed 15,000 and 11,000 people respectively, but with better warning systems, there have been less than two dozen casualties since the late 70's.

What is a super typhoon? It is equivalent to a Category 5 hurricane. Different ocean basins have different rating scales for their storms. Remember that in the Atlantic, big storms that rotate and have an eye are called "hurricanes." In the Pacific, they are called "cyclones." In most ocean basins, hurricanes are rated in "categories," with values assigned from 1-5. Here is a NOAA table of categories:

A "super typhoon" is defined as a storm that reaches maximum sustained winds of at least 65 m/s (234 km/hour), so it is equivalent to a Category 4-5 cyclone. The term "major hurricane" is also used, and it is used for storms that have maximum sustained 1-minute surface winds of at least 50 m/s or 180 km/hour, so applies to Category 3 storms and stronger.

September floods in Boulder County, Colorado--monsoons

The monsoon setting over Colorado

According to the National Weather Service, as of 8:20 a.m. this morning, Boulder has received 9.64 inches of rain this month, breaking the old record of 5.50 inches set back in 1940. Most of this rain fell overnight. The heavy rain resulted from warm moist air flowing in from the south colliding with cool moist air coming from the north and east. The pattern is expected to continue through the end of the week.
           According to the National Weather Service, the "southwest monsoons" usually begin around the second week of July when an area of high pressure breaks away from the main Pacific ridge and settles in over the Great Basin, bringing hot temperatures during June and early July. This high center moves eastward across the Continental Divide and into the Central Plains (more or less what you see in the graphic above), followed by a slightly cooler but very moist environment brought in by southwesterly flow behind the high. The monsoon is typically over by the end of August, but can continue as late as October. To quote the NWS site "In fact, many areas in southwest Colorado and southeast Utah experience a secondary precipitation maximum in October due to late-season tropical storm moisture that's been carried northward by the monsoonal flow."
         The monsoon moisture does not produce thunderstorms every day, but has a pattern of "bursts" and "breaks." A "burst" is a movement of a weak trough into the upper level westerly winds. It spreads upper level cold air into the region. Meanwhile, the lower levels of the atmosphere experience strong surface heating and transport of moisture from the southwest. These two conditions create a very unstable atmosphere, leading to widespread thunderstorm outbreaks.  A "break" occurs when an enhanced ridge of the Pacific subtropical high pressure moves inland and cuts off the moisture flow, thus stabilizing the atmosphere.
          The monsoons are welcomed because they offer a break from accumulating hot days in June, but they also result in deadly flash floods. As I write this (3:00 PDT) flooding is leading to evacuations in Denver, I-225, I-270, I-70 and I-25 all are experiencing flooding and traffic jams, CU Boulder is closed today and tomorrow, and 5 dams are overtopping or burst. A life-threatening flood emergency has been in effect in Boulder and northern Jefferson counties since last midnight. Three people have been killed due to flooding, and lengthy flash flood warnings and watches are in place.

"The Big Problem with Disaster Planning"

Back in action after a much needed summer break!

About three months ago, Time Ideas (a section of the online version of Time magazine) asked me to write an article about problems with disaster planning. Now the copyright agreement allows me to post that article here:

We know that a tornado will bring howling winds and drenching rain, that a volcanic eruption will blanket the countryside with ash or lava, and that an earthquake will violently shake the ground. These are some ways in which Mother Nature unleashes the energy stored in the earth, and we can try to anticipate and prepare for the results. We can build basements and shelters to protect us from those tornadic winds, flee from the countryside when the volcano erupts, and reinforce our infrastructure from the quaking ground. But we have not always anticipated the chain reactions that these natural disasters often trigger.

(MORE: 2013 Hurricane System to Be Extremely Active)

The tornadic winds in Moore, Okla., last week and in Joplin, Mo., only two years ago killed many victims by blunt force trauma, but people also died from less direct causes. In Moore, it appears that at least six children, who should have been safe in a basement, died from asphyxiation when water, possibly from broken pipes, flooded to the low point where they were sheltered. Several people in Joplin died from a rare and difficult-to-treat fungal infection called zygomycosis. It turns out that people who have sustained massive traumatic injuries become so stressed that their immune systems find it difficult to fight off infections, paving the way for pathogens to enter the body and thrive. It took teams of experts from the local, state and federal level to figure out that the people who were displaying these symptoms had been impaled during the tornado by projectiles containing soil, and that the infections arose from a fungus in the soil.

(MORE: Tornado Warning: U.S. Weather-Forecasting Service Needs Major Upgrades)

In the harbor of Port-au-Prince, Haiti, much of the damage from the 2010 earthquake was not from direct shaking, but from the fact that the solid ground supporting the wharfs turned to mush during the quake, a process known as liquefaction. This, in turn, closed the harbor to rescue efforts to bring aid into the area. The same process caused multistory buildings in San Francisco to sink up to their second or third floors in the Loma Prieta earthquake.

And in the classic historic example of the eruption of the Icelandic volcano, Laki, in 1783, the tens of thousands of people who died as a result were mainly the victims of famine. Although the eruption was relatively small (a 6 on a volcanic scale of 8), the volcano spewed out around 8 million tons of hydrogen fluoride and 120 million tons of sulfur dioxide over an eight-month period. Half the cattle, 80% of the sheep and 20% of the people of Iceland died in the event now known as the “Mist Hardships.” The sulfurous clouds spread across Europe and around the world, weather patterns changed, crops failed and the deadly famines developed.

(PHOTOS: Tornado Flattens Suburb Outside Oklahoma City, Kills Dozens)

If we want to improve our odds of surviving disaster, we need to do two things. First, we need to be prepared for the rarest, biggest events. Currently we invest in infrastructure to protect us from the smaller events — be they tornados, eruptions, earthquakes or even small tsunamis that can be shut out by common storm wave barriers on exposed coastlines. But, we rarely have made the costly investments necessary to protect us from the rare, but truly devastating, big events.

(MORE: Viewpoint: Don’t Call the Planet ‘Mother Earth’)

Second, we need to learn much more about the secondary reactions and raise more awareness that it’s not just the primary disaster we have to anticipate. In order to enhance public safety, civic leaders and emergency responders as well as members of the general public must understand the links in the chain. By improving our emergency-response system and educating the public so that people are willing to support such efforts, we can greatly improve our readiness for the next inevitable outburst of Mother Nature.

Kieffer is a professor emerita of geology and physics at the University of Illinois at Urbana-Champaign and the recipient of a MacArthur Fellowship. She is the author of the forthcoming book Dynamics of Disaster and writes regularly on her blog Geology in Motion.

Read more: http://ideas.time.com/2013/05/28/the-big-problem-with-disaster-planning/#ixzz2dT5dl5K1

Earthquakes in New Zealand--why?

Location of today's earthquake in New Zealand
from this site. Note that the earthquake was on the South Island,
whereas Wellington is on the southwestern tip of the North Island.

New Zealand has again been shaken by a series of earthquakes. The largest, at magnitude 6.5-6.6 struck Friday, and was followed by several smaller aftershocks with magnitude about 5.  Although these are "moderate" sized-earthquakes, they are capable of causing widespread damage if near population centers. Fortunately, these were not and, also fortunately, New Zealand has strict building codes. Even so, chimneys collapsed, roofs caved in, and a bridge collapsed on a major state highway. The earthquake was 94 km west of Wellington, the capital, at 10 km depth was fairly shallow. Bill Fry, a seismologist with GNS in Wellington said that the quake was similar to a 6.4 tremor that struck in the same area on July 21, and appears to be a continuation of a sequence that started with some of magnitude in the high 7's.

Tectonic setting of New Zealand
from Wiki here   

     The most powerful earthquake in New Zealand's recent recorded history, a magnitude 8.2, struck Wellington in 1855, although there are stories of earthquakes in the Maori legends. Wellington sits on the coast and was thrust upward so far by the quake that the shoreline receded 200 meters. Here is a great site with details of many of the major earthquakes.
     New Zealand has a wide variety of active geologic phenomena--earthquakes, volcanic eruptions, geothermal areas, and landslides--because it sits at the boundary of the Australian and Pacific Plates. In the north (see graphic) the Pacific Plate is subducted under the Australian Plate, but in the south, the reverse happens: the Australian Plate is subducted under the Pacific Plate. These two subduction zones are connected by the Alpine Fault that runs along much of the west coast of the south island of New Zealand. Subduction rates are high--tens of millimeters per year, but so are erosion rates. The mountains rise about 10 mm/year, but are eroded down at about the same rate. The combination produces some of the most beautiful mountains in the world on the south island. The Alpine Fault is considered to be at high risk of producing a major earthquake in the next 40 years (see GNS).
    Recent activity has been in the vicinity of the Marlborough fault system and, in particular, the M7.1 Canterbury (2010) and Christchurch (2011) earthquakes were on relatively minor faults. The fault system was named after the 1848 M7.5 earthquake centered in the Marlborough district of the South Island, a quake that produced substantial damage in the Wellington area as well. The European population of Wellington was approximately 4500 at the time; only 3 people died. Because stone and brick buildings suffered much more severe damage than wooden ones, for a time many buildings in the area were constructed of wood. But, after only 25-30 years, the institutional memory was lost and stone and brick buildings returned, partially encouraged by concerns about fire.  At the beginning of the 20th century the country seemed calm, and the New Zealand Official Yearbook included the comment: "earthquakes in New Zealand are rather a matter of scientific interest than a subject for alarm." Quote from this source. The population of Wellington in 2012 was 385,600.

Mount Rokatenda (Paluweh) Volcano, Indonesia, erupts; six dead

Mount Rokatenda in eruption
Photo from BBC.com here

Mount Rokatenda*** north of the island of Flores in Indonesia erupted on August 10, killing 6 people. It has been erupting since late 2012. Eruptions were generally VEI 3 in intensity.  A 3 km exclusion zone was set up, and many residents of the island (~3000? according to an AP story) were evacuated, with many moving to the main island of Flores, but some refused to leave, growing used to the moderate volcanic activity.

Paluweh and its eruption centers
Originally from Neumann van Padang, 1930
as reproduced in his 1983 article

     Scientific literature about this volcano is sparse, and the best that I found was "History of the volcanology in the former Netherlands East Indies" by Neumann van Padang, Scripta Geol. 71, pp. 1- 75, 1983. Reading this paper, with its four beautiful color plates brought back memories of the two famous photographers of volcanoes, Katya and Maurice Kraft who were killed in a pyroclastic flow during the eruption of Mount Unzen. Katya and I had roomed together at a field conference in the Caribbean.
    The first sighting of this volcano appears to have been in 1856 by Francis, who called it Luca Raja; Buddingh in 1861 called it Palowe. When spotted by Kemmerling in 1921 it has a "partly barren, partly wooded summit."
    Paluweh rises 3,000 meters from the sea floor, and is 875 m high above the water. It has the classic, though somewhat asymmetrical, stratovolcano conical structure though appears highly gullied from the topo map in Padang's figure 13. The summit region has a complex of small cones. These appear to be somewhat south of the main summit (see figure to the right). Documented eruptions were in ~1650, 1928, and 1972.

March 31, 2013 NASA image of Paluweh/Rokatenda
showing devastation on the south side of the island

      ##. Ash and pumice, estimated at 19.5 million cubic meters (corresponding to about 4.6 million cubic meters of lava) were erupted, and a new lava dome of about 8 million cubic meters as formed.
Paluweh erupted in August-September 1928. The eruptions took place from a collapsed area south of the summit where six ancient craters and three lava domes had been found. During the August eruption three new craters were formed, and a fourth on September 9th.  During the august eruptions there were "sea waves" with heights of 5-10 m (tsunamis) that attacked the island itself, killing 128 people out of the total population of 266.
     Flores is near the eastern end of the Indonesian arc, west of East Temor and northwest of Darwin, Australia. The geology of Indonesia is extremely complicated. It lies at the intersection of three of the major lithospheric plates: the Indo-Australian Plate, the Philippine Plate, and the Eurasian Plate. These plates intersect at angles, leading to a complex network of faults in the region (and to the intense earthquakes that plague the area). These collisions produce deep trenches (Java, Timor, and Philippines Trenches) and island arc volcanoes.

Simplified plate boundaries in Indonesia.
From here.
Although blurry, Flores can be seen just above the
intersection of the Java and Timor Trenches.

***In researching this, I found different spellings: Rokatinda, Paluweh, Paloweh, Palu'e,  Luca Raja, Palowe. In the article referenced above, I think that the stratovolcano and the island that it occupies are referred to as Paluweh, and the summit crater as Rokatenda and I follow that nomenclature here. The "Palu..." names were Dutch origin; the Rokaa... names were the new Indonesian names. It is about 1250 miles east of Jakarta.

##The population now is estimated as about 10,000.

Here are other references to this volcano: The Smithsonian Global Volcanism Program here.
Volcano Discovery here.

Steamboat geyser erupts!

AP Photo/Robb Long

One of Yellowstone's most spectacular geysers erupted today, making headlines in major newspapers and radio news shows. Why such a fuss? Steamboat erupts to hundreds of feet, but only rarely and never predictably. Having worked in Yellowstone studying the geysers, I can imagine the excitement of the tourists as they hear the roar of the geyser erupting, see the towering plume, and perhaps get showered by its steam and droplets (hopefully not by any entrained rocks or sand). I wonder how many have glasses or camera lenses that now bear witness to the chemicals in Steamboat's water with fine deposits of minerals precipitated when that water evaporates?

What is a geyser? Is Steamboat really a geyser or should it be called a "hydrothermal explosion?" Geysers are usually defined as systems of hot water that intermittently ejecta some or all of their water into plumes consisting of water and steam. Geysers lie along a spectrum of thermal features that range from hot springs (warm to scalding) on one end and fumaroles on the other. A fumarole spouts dry or wet steam, usually continuously, but sometimes intermittently. Geysers can be thought of as hot springs that intermittently eject the hot water from their reservoirs.

The activity of a particular thermal feature in an area like Yellowstone depends on a delicate balance of heat and water (heat is supplied by hot water, vapor, or gases that rise from magma at depth; most of the water is circulating cool groundwater that is heated by the magmatic hot water or gases, or by contact with surrounding hot rocks). Too much water and you have a hot spring. Too much heat and you have a fumarole.  Just a right balance and you get a geyser that discharges and recharges its heat and water in cycles. (There are even cold "geysers" that charge and recharge carbon dioxide, but that's another story!)

Conduit of Old Faithful

What does the reservoir of a geyser look like? We don't know for most geysers as it is difficult and dangerous to try to find out. However, in the 1990's, with the permission and assistance of the National Park Service, we lowered an ice-cooled miniature video camera into Old Faithful. This was in the days before truly miniature videos were available, and our system had to be less than 4" diameter to pass through a known constriction, had to contain its own lighting system, had to be cooled with ice because it was in an environment of 92 C steam, and had to have a heated lens to prevent condensation on the otherwise cool unit.  My colleague Jim Westphal at Caltech cleverly designed the system. From this work, we were able to constrict the cross-section of Old Faithful shown to the right. The reservoir is a tortuous series of narrow and wide spaces.  Researchers in Russia have probed geysers there and found similarly complex conduits, and it is likely that the reservoir of Steamboat Geyser is a similar complex of caverns and constrictions.

That word "intermittently"in the definition of a geyser is taken by many to mean "regularly" and somewhat "predictably." So, tourists get used to the fact that the National Park Service can tell them within about 10 minutes or so when Old Faithful is going to erupt; and within several tens of minutes or several hours for a number of the other geysers around Yellowstone.

So, what is Steamboat? It is a geyser if the word "intermittently" is used properly. But, the eruptions are so rare that they do resemble those rather nasty events called "hydrothermal explosions." The term "hydrothermal explosion" is usually used to describe a new feature--one that has popped up where no known feature, such as a geyser, existed before.  The vent of Steamboat is so large that it is well-known, and the boardwalk for tourists passes right by it so one can look down on its vent. But, just as some tourists probably got taken by surprise if they were close to Steamboat when this mighty eruption (reported to have been 200-300 feet high for 9 minutes) took off, tourists in the thermal basins are always at risk of a true hydrothermal explosion. That's one reason for staying on the boardwalks constructed for walking through these basins--they are built in areas deemed as safe as possible from future surprises.

**Reference: Hutchinson, R., Westphal, J., and Kieffer, S., In situ observations of Old Faithful Geyser, Geology, 25(10), 875-878, 1997.

Links between earthquakes and other geologic activity

Nature Geoscience (August volume 6(8), pp. 585-672) has a fairly long section ("a Web Focus") and a number of papers on geologic activity associated with or triggered by earthquakes. The introductory editorial reflects that in 1835 Charles Darwin voyaging on the Beagle experienced a large earthquake near Concepcion, Chile, and noted that within the hour a train of volcanoes in the Andes spouted out a dark column of smoke (though it would take a journey into Darwin's notes to determine whether he thought this was volcanic gas or perhaps debris from landslides. The implication in the editorial is that it was the former).
   

Illustration of the elastic rebound part of volcanic arc
subsidence after a megathrust earthquake

The first paper in this section (by Sigurjon Jonsson) summarizes the deflation of volcanic areas in response to the 2011 Tohoku and 2010 Maule (Chile) earthquakes. Both settings are at subduction zones (see figure), and the volcanoes that subsided were on the overriding plate. Prior to the earthquake, strain accumulates and compresses the overriding plate. During and after the earthquake, the overriding plate extends and subsides. However, subsidence beyond that which can be explained by this process is observed.
     In the case of the Tohoku earthquake, Takada and Fukushima documented 5-15 cm of subsidence at a distance of 150-200 km from the rupture earthquake, but no volcanic eruptions. They suggest that subsidence is caused by sinking of magma reservoirs and their warm host rocks through the colder surrounding crust. Prichard and colleagues noted that two earthquakes (1906, 1960) were followed by eruptions in the Andes within a year, but that no eruptions have been clearly associated with the 2010 earthquake. They were, however, able to document the 15 cm of subsidence, and suggest that hydrothermal fluids were released from hydrothermal systems surrounding the volcanoes in Chile during the 2010 quake, and that the escape of these fluids caused the volcanic areas to deflate.
     A second example of a proposed connection between earthquakes and geologic activity is more controversial: the Lusi mud volcano eruption. In 2006, mud erupted through and around a drill hole, flooding towns and displacing thousands of people.  Paul Davis summarizes a paper by Lupi et al. that proposes that the 2006 Lusi mud eruption in Indonesia (still continuing) was triggered by a M6.3 earthquake two days prior to the eruption and 275 km away.  Lupi et al. argue that strains, which are unarguably small at such a distance in homogeneous media,  were amplified by a downward concave layer of shale that acted as a parabolic reflector. Their simulations suggest that the stresses could have been about 100 kPa, five times higher than original estimates of 21 kPa. Such pressures, the assert, could have liquified the mud that resides at depth, resulting in the eruption of mud through the drill hole. This conclusion remains controversial (see discussion by R.J. Davies, et al., Earth and Planetary Science Letters, 272, 627-638, 2008).
     For a third example, Fischer et al. examine subduction zone earthquakes as triggers of submarine hydrocarbon seepage.  Offshore of Pakistan, the Arabian Plate subducts beneath the Eurasian plate. This is a region of intense seismicity, in particular a major earthquake (M8.1) occurred there in 1945. It occurred in an area where gas hydrates (methane clathrates) are present, and leakage of hydrocarbon gas is known to occur here. Methane and sulfates both occur in the ocean with sulfate being stable above about 5 mbsf, and methane at greater depths. The concentration of both goes to nearly zero at a depth known as the sulfate-methane transition (SMT). In a complicated chemical reaction, sulphate is consumed through anaerobic oxidation of methane (CH4 + SO24􏰀 ! HCO􏰀3 + HS􏰀 + H2O). Barium, being present in sea water, is precipitated at the SMT in so-called "barite fronts" and the abundance of barite can be used to reconstruct changes in upward methane flux.  The authors calculated that it would take approximately 38-91 years to produce the observed barite enrichments. This leads them to conclude that the barite production could have been initiated by the 1945 earthquake and an accompanying increase in methane flux due to release from the hydrates. If confirmed, submarine gas release triggered by earthquakes needs to be added to the list of processes that can add methane to the hydrosphere, and possibly to the atmosphere, in the carbon budget.




References: Takada, Y., and Fukushima, Y., Nature Geoscience, 6, 637-641, 2013.
Pritchard, M.E., Jay, J.A., Aron, F., Henderson, S.T., and Lara, L.E., Subsidence at southern Andes volcanoes induced by the 2010 Maule, Chile earthquake, Nature Geoscience, 6, 632-626, 2013.
Lupi, M., Saenger, E.H., Fuchs, F., and Miller, S.A., Lusi mud eruption triggered by geometric focusing of seismic waves, Nature Geoscience, 6, 642-646, 2013.
Fischer, D., et al., Subduction zone earthquake as potential trigger of submarine hydrocarbon seepage, Nature Geoscience, 6, 647-651, 2013.

Gansu, China, rain, mudslides, and now a shallow earthquake: are they related? And, was that shallow earthquake notice right?

A map showing the location of the December 16,
1920 M 7.8 earthquake
From Wiki here 

An alert has just come out over the USGS earthquake network that there was a very shallow (1 km depth) magnitude 5.9 earthquake in Gansu province, China, 13 km east of the city Chabu (or, later reported as 156 km west of Tianshui.). Interestingly, two other agencies give very different estimates of the magnitude and depth: a 6.3 at 10 km depth by GFZ (at the Helmholtz Centre in Potsdam) and a 6.1 at 15 km depth according to EMSC (the European Seismological Centre), as reported here. And, while I was checking this on the EMSC site the numbers changed before my eyes to a M6.0 at 10 km depth! It would have been interesting to see how this all sorts out--if the USGS depth of 1 km is correct, this is a very unusual earthquake, and I wonder if it is actually an event associated with a major landslide rather than a fault zone (this was the case on May 18, 1980 when the north flank of Mount St. Helens failed into a big landslide). However, when I checked into the USGS site here, the depth is now listed at 9.8 km.  Makes me wonder what that earlier bulletin was all about!

The epicenter appears to have been Dingxi City. Dingxi is a "prefecture level city" in the southeast of Gansu province. It's area covers 20,300 sq. km, and the population is reported as 2.7 million people (in 1 urban district, 6 counties, and 119 towns). It was an important city in early development of some of China's cultures because the Wei River, one of the Yellow River's biggest tributaries, flows here.  The surrounding terrain hills and ravines cut into the loess deposits, weak sandy deposits, possibly water-saturated from the recent rains. This does not bode well for damage.

 The earthquake occurred near midnight UTC on July 21. This follows, by only 8 days, a major landslide that reportedly trapped at least 100 tourists after a landslide cut off a road during a week of storms that have flooded rivers and triggered mudslides. At least 86 people were reported to have died by Chinese state media. Mudslides and floods are common in the mountainous areas of China, but this year seems to have been an especially bad one in many areas of Asia.

Map showing the relation of todays earthquake to
the major city of Tianshui.

In 2010, a deadly mudslide killed approximately 1500 people. After heavy rains, water built up behind a dam of debris that blocked a small river north of the city of Zhugqu. The dam broke, sending nearly 2 million cubic meters of mud and rocks through the town in a surge tens of feet high. A major problem in this area is that the forested areas have shrunk (by as much as 30% according to Wiki), and the reserve of timber has diminshed by 25% due to harvesting (these are 2010 numbers, and are relative to a base in the 1950's.) It is a region of massive construction of hydroelectric projects.

Gansu is also a region with many earthquakes.  In 1879, an earthquake with an estimated magnitude of 8.0 and Mercalli intensity XI (extreme) killed an estimated 220,000 people. This earthquake was preceded by foreshocks for a few days. The earthquake also triggered landslides that dammed local rivers up to 40-120 m.

Today's earthquake appears to be followed by numerous aftershocks, though it is difficult to tell where they are relative to the initial location given as 13 km east of Chabu. Some are reported at a distance of 156 km from Tianshui in Gansu province, a city of 3.5 million people.

A reader pointed out a site that covers earthquake preparedness here. Thanks!!

Heat Index vs. Humidex

From this site

It is, at the moment, 91 F in my former home town of Urbana, IL, the dew point is 75 F, the relative humidity is 59%, and the Heat Index is 102 F! In Toronto, Canada, it is 33.3 C (92 F) in  the humidity is 46%, the dew point is 67 degrees and the Humidex is 40 C (104 F). 

In contrast, where I live here near Seattle, the temperature is 73.7 F, and Weather Channel reports that "it feels like 77 F" (that's a jargon for the Heat Index.) The humidity is 57%, the dewpoint is 58 F.


What do these numbers mean, and how are they related to each other? First or all, a disclaimer: when I put those last numbers about temperature, dew point, and humidity into the NOAA government calculator that I cite below, I do not get the same answer as Weather Channel (77F); I get 74 F.  Either way, it's very comfortable here in the Pacific Northwest compared to conditions in the Midwest and eastern U.S. See below for further comments.

One difference is that Canadians use the Centigrade scale and we are stuck with the awkward Fahrenheit scale. However, it is possible to go back and forth between the two scales with some rounding off.  A simple way to interpret the Humidex is that it is equivalent to the dry temperature--that is, if the temperature is 30 C (86 F) and the calculated Humidex is 40 (104 F), then the humid heat "feels like" a dry temperature of 40 C (104 F).

The other differences are more complicated, and I have to say that--having lived in both countries--I had to laugh when I saw on Wiki that  "A joint committee formed by the United States and Canada to resolve differences has since been disbanded." Both scales use vapor pressure or dew point for the calculation, but the Canadians (perhaps because it is colder there?) use a dew point base of 45 F (7 C) for the humidex, whereas we Yanks use 57 F (14 C). The Heat Index, however, incorporates variables other than the vapor pressure, including 
The Heat Index formula is:


where the c's are constants, disputed by experts.

The Humidex formula is;


The Humidex is higher than the US Heat Index at a given temperature and humidity. A mathematical scientist looking at these two formulas would instantly wonder two things: it's amazing that they are even close to each other because of the difference in form, and they must apply over very restricted temeprature ranges because of the nonlinear dependence on R (relative humidity) and temperature (T).

In terms of discomfort, the above graphic illustrates the various levels of discomfort and danger on a Heat Index scale. Here are the rough rules used by Canadian weather forecasters for Humidex:

Less than 29°C, no discomfort
30°C-39°C, some discomfort
40°C-45°C, great discomfort
45°C-54°C, dangerous
Above 54°C, heat stroke imminent

Here's a national weather site that allows you to use either F or C, and either Dew Point temperature or relative humidity, to calculate the Heat Index. (The numbers will be slightly off because of rounding errors.) Here's a commercial site for calculating Humidex. Note that by the U.S. Heat Index chart, our Seattle conditions at 73.7 F aren't even worth putting on the chart! And, my guess is that the reason the calculators that I provide here give wierd answers for the Seattle situation is that the formulas just aren't very good at these "low" temperatures.

Do heat waves extend to outer space? And, EVA the space-flying cow.

Two members of the launch and recovery team
point to EVA the cow where she landed
in Death Valley. Photo from the
Facebook.com reference.

"Earth to Sky Calculus" is a group of middle and high school science enthusiasts based in Bishop, California. Since 2011 they have launched 30 balloons into the stratosphere, with 18 recording temperatures at the tropopause, the boundary between the tropopause and the stratosphere. They are hoping to do a satellite launch in 2013.
       Last month, when a heat wave swept across the U.S. Southwest, with temperatures in Death Valley reaching as high as 129 F, the students decided to find out if the heat wave extended all the way into space, that is, up into the stratosphere. On June 30, when it was 108 in Bishop, they launched a research balloon that had onboard a cryogenic thermometer and measured temperature up to 90,000 set. The thermometer registered a "low" temperature of -64.4 C, where the balloon passed through the tropopause. The troposphere is the coldest part of the atmosphere, and it was just as cold as usual on that day. Their measured temperatures ranged from about -68 C (-90 F) to -55C (-67 F).** The answer was: heat waves to not extend up to the tropopause.

A Google search about the Earth to Sky program reveals a video of  EVA the cow (from Tauranga, New Zealand) who, on April 22, 2013, they sent on a weather balloon to the edge of space. EVA successfully parachuted back into Death Valley. It took the students 18 hours to find her! This is a truly cool video!

The students have launched other items including a bobblehead of President Barack Obama on the day before Election Day in 2012. These kids look like they are having a lot of fun and learning a lot as well. Kudos to them, their families and teachers!

**This material from their Facebook page.

Tea leaves defy gravity, move upstream

Mate tea in a calabash gourd
Photo by Jorge Alfonso Hernandez
from Wiki

Water flows downstream, right? So, how can particles, such as tea leaves or chalk particles, floating on downstream-flowing water move upstream? This is a puzzle tackled by researchers recently. In work summarized in Science News here, Sebastian Bianchini describes how, one night when he was an undergraduate in 2008, he was making tea and noticed that by the time he had filled his cup containing tea leaves, some of the tea leaves had marched up into the pristine water in the kettle. In a sad comment on the difficulty of getting unusual work published, he and a physicist at the University of Havanna in Cuba, were unable to get their work published, even though it included some experiments.
    Last year, the duo met Troy Shinbrot, a physicist at Rutgers. Troy replicated the experiment, setting one tank of water 1 cm higher than another. The water flowed down an inclined channel, and into a waterfall 1 cm high.They added chalk and mate tea** to the bottom tank and observed the particles moving up to contaminate the upper tank. The flow is complicated in 3-D: the particles climb up the backside of the waterfall in a series of vortices, to the outside of the channel, and then can be transported back downwards through the center of the channel and over the front of the waterfall.

The experimental setup for the tea leaf experiment
Figure 1 in the referenced paper

     They hypothesized that the tea leaves in the lower tank disturbed the surface tension (bonds of hydrogens that create an elastic network at the surface) and that the particles moved up toward the pure water where the surface tension was higher, effectively climbing along the top of the water surface in defiance of gravity.
     The effect had been recognized earlier by physicists, but the magnitude had not been realized. In a simple back-of-the envelop analysis, the authors show that the surface tension difference between the lower (tea-contaminated) and upper (pure water) reservoirs is about 0.01 N m-1, and that the acceleration (for typical chalk particles) would be about 20 times gravity.
     To test the hypothesis that this is a surface tension effect, the authors dropped a liquid surfactant into the upper and lower reservoirs. When it was dropped into the upper reservoir, the contamination was abruptly eliminated, whereas when it was added to the lower reservoir, the contamination was initiated (if it had not already begun) or accelerated (if it was in progress.) In supplementary material, there are detailed 2-D simulations. There are many more experiments and quantitative analyses in the paper.
     Does this experiment have practical implications? The authors don't know yet, but are suspicious that particles might migrate upstream in a slow-moving river, or be able to sneak into the tips of laboratory pipettes, contaminating samples.

**Mate tea is a traditional South American tea made by infusing the leaves of yerba mate with hot water. The traditional way of brewing it is shown in the picture above.

Reference:

S. Bianchini et al. Upstream contamination by floating particles. Proceedings of the Royal Society A. July 3, 2013. doi: 10.1098/rspa.2013.0067.

M6.1 earthquake strikes Indonesia's Aceh province

     In 2004, an earthquake of estimated magnitude 9.1-9.3 off Aceh province in Indonesia triggered a tsunami that killed an estimated 230,000 people around the Pacific Rim in Asia. Today a much smaller, M6.1 struck, killing at least one person (possibly many more, news reports are still coming in), leaving two others missing, dozens injured, and several dozen homes damaged. The earthquake caused at least one landslide.

Map of Indonesia; the red square near Jakarta shows the
location of the 2012 M8.2 aftershock
From this site.
Today's M6.1 quake was at about 1:00 to the NE of the
epicenter of the 2004 quake (shown as the big
bull's eye on the left) in the center of the tip of
Sumatra.

     This is not the largest earthquake to hit Indonesia since the 2004 event; one quake, centered beneath the ocean floor and roughly 300 miles from Banda Aceh (the capital of Aceh province), was a M8.6. It was followed by a M8.2 aftershock. It is humbling to remember that a relatively small earthquake like today's M6.1 kills people, and would be major news if it occurred in the U.S. That people in Indonesia live with these killer quakes all of the time should not be forgotten.
    The 2004 event was located about 100 miles off the western coast of northern Sumatra at a depth of 19 miles below sea level (today's event was, in contrast, only about 6 miles deep and was centered below land; see map and caption). A huge section of length 810 miles ruptured during this quake. The main rupture was followed by secondary faulting (dubbed "pop up faults" on Wiki" that acted in concert with the main rupture to produce the massive tsunami that caused so much destruction around the Asian Pacific Rim. The total length of all of the faulting, which took place over several minutes, was about 1000 miles.

What's up with the weather in the Pacific Northwest?

500 hPa contours for Monday, 5:00 p.m.
From Cliff Mass blog referenced in text
Note the N-S alignment of the contours
as discussed in the text. The low is the red
area offshore of the northwest; the high
is the blue region centered over Idaho. This
system has been migrating from east to west
over the past week.

    CliffMass.blogspot.com" and again refer you to it regarding the nation's weather--particularly the weather in the Northwest. Mass is a professor at the University of Washington in Seattle; here is his home page. His posts of Wednesday and Friday, June 26-28, discuss the upcoming heat wave in detail. Note: this heat wave follows a cold and wet spring, and is only a week before the infamous July 4 date when "summer comes to the Northwest."
 I have several times referred to one of my favorite blogs "
     Briefly, the whole west coast is heating up, with the highest temperatures off the coast in the interiors of Washington and Oregon, with somewhat lower, but still high temperatures, in eastern California and western Nevada (Death Valley could be interesting). Last week (which was wet and cool here) there was a VERY deep low (italicization same as Mass) over the eastern Pacific, and a high-pressure ridge over the Rockies and western Plains. This setup (at the 500 hPa height) allowed moist air to flow in from the southwest. Yesterday (Friday) the low center and the high pressure ridge moved westward, the high-pressure ridge intensified, and the Northwest dried out. By Monday, the high pressure will intensify and will be located west of the Rockies. The low and high regions are getting "squashed" from east to west, aligning the pressure contours in a north-south configuration. Since the winds follow the contours, warm air will flow into the Northwest from the south. This pattern will continue into Tuesday, bringing dry hot air up from the south into the Northwest. The highest temperatures will be east of the Cascades, but they will not be record breaking. To have new records in western Washington, the ridge would have to be further westward than it currently is, essentially sitting on top of Seattle. Mass predicts that on Monday there is a chance of a record high at SeaTac airport; the current high for that date is 87 F.

CAPE index for Monday and Tuesday
From the Cliff Mass blog referenced in the text

     I have now moved to the Northwest from the Midwest, thinking that I left thunderstorms behind me. WRONG! In a very unusual situation for the Northwest, it is possible that there could be some severe thunderstorms in the region, largely along the Cascades in Oregon. There is a measure of thunderstorm potential called CAPE (Convective Available Potential Energy). Typical high values of the CAPE are a few hundred in this region; it is projected to reach 2500-3000 Monday and Tuesday. However, countering the tendency for massive convection that would cause thunderstorms, is a sinking motion of the high pressure ridge and a lack of strong upward convective motion that would release the energy. Mass says, however, that "the models would not have to be very wrong for something very interesting and very severe to happen. Need to watch this."

The Great Pacific Garbage Patch and ??The Great Lakes Garbage Patches???

Add caption

NOAA has, over the past few years, made a rather big deal of a stagnant zone in the East Pacific Ocean where garbage, including plastics, are accumulating. For example, on the left is a photo from the NOAA Marine Debris Program showing garbage (though this garbage is on a beach, not in the Pacific), including "microplastics", plastic pieces less than 5 mm long. Plastics in the ocean do not fully degrade, but weather into smaller and smaller pieces. These, in turn, are dangerous to marine life. Here is an excellent summary and fact-file related to this problem.

Several myths have grown up about the "garbage patch," worth clarifying here:

(1) It's not really a "garbage patch," e.g., a floating landfill. Rather, the debris consists mostly of small bits of plastic suspended throughout the water column. A good analogy is that it is more like flecks of pepper floating throughout a bowl of soup, than a skim of fat that sits on the surface. There are three major garbage patches stretching to the west from the coast of southern California and Baja: the Eastern Garbage Patch, the Western Garbage Patch out near the Kuroshio current, and, further north between these two, a subtropical convergence zone.

Graphic is from Tomczak, M., and Godfrey, J.S., 2002,
Regional Oceanography: an Introduction, online version.
A is a convergence zone; E is a coastal upwelling
divergence zone. Black arrows are winds; green arrows
indicate water movement. This graphic from
this WWW site. 

        (2) There is not just one, but many garbage patches. They form at "convergence zones" in the ocean. A convergence zone is a place where water, and plastic, accumulate in the center of rotating winds. An example is shown in the graphic to the right.  When there is a high pressure weather system in the North Pacific, air moves from high pressure to low pressure, deviation continuously to the right because of the Coriolis Force, which causes the wind to blow in a clockwise circle around high-pressure weather systems. The water curls to the right of the wind. Together they create a zone of convergence in the center, A in the graphic. As new water is brought into the system by the winds, water that was there sinks. However, the plastic doesn't sink with it and gets left behind, accumulating in the upper part of the water column. The process works in reverse in the adjacent low pressure system--water diverges away from the rotating winds. Plastic accumulates in the convergence zones.
     In an interesting post on May 16 by the NOAA Office of Response and Restoration, the question "Is there a garbage patch in the Great Lakes?" is asked. In an understatement, NOAA points out that "The Great Lakes are no mere group of puddles. They contain nearly 20% of the world's surface freshwater and have a coastline longer than the East Coast of the United States."

Average summer water circulation in the Great Lakes.
From Beletsky et al., 1999 as posted by NOAA here.

In the Great Lakes system, water flows from the big Lakes Superior and Michigan in the west into Lake Huron, through Lake St. Clair (not shown**) and the Detroit River into Lake Erie. It exits through Niagara Falls and Lake Ontario into the Saint Lawrence River and then out to the Atlantic Ocean. Within each Lake, the "current" breaks down into numerous eddies (convergence zones similar to those discussed above) whose geometry is determined by the elevation differences (highest in the west, lowest in the east), the geometry of the Lake beds, wind, solar energy, differences in density in the water column due mostly to the temperature differences, and the shorelines. There is now a project based at the University of Waterloo in Canada, partnered with COM DEV (a designer and manufacturer of space and remote sensing technology) to develop and test remote sensing methods for detecting plastics in the Great Lakes. Here's Sarah Opfer's blog on this topic for more information.

**Lake St. Claire is the small nearly-circular feature shown on this map between Lake Huron and Lake Erie.

A "shocking" start for life on Earth?

A schematic of the synthesis of nonbiological hydrocarbons
during impact of simple icy comets on the early Earth
Image from DOE/Lawrence Livermore National Laboratory
as published in ScienceDaily.com 

ScienceDaily.com has reported on a paper in press for the  January 20, 2013 Journal of Physical Chemistry A. The authors are from Lawrence Livermore Berkeley Laboratory (LLBL) (Nir Goldman) and the University of Ontario Institute of Technology (Isaac Tamblyn, who is a former LLNL postdoc). The exciting conclusion of the work is that it is possible that during the short duration of a comet impact, shock waves could have provided the necessary conditions (pressure and temperature) and energy (heat) to allow chemical reactions that would have produced prebiotic hydrocarbons such as nitrogen-containing heterocycles. These are believed to be the prebiotic precursors to DNA and RNA base pairs.

The structure of pyridine, C5H5N
Wiki image by Calvero

       What are "nitrogen-containing heterocycles"? A heterocyclic compound is a ring-structured compound, with the "hetero-" meaning that there are atoms of at least two different elements in the ring (the opposite of a homocyclic compound that has only one element in the ring). They can be inorganic, but the ones of interest contain at least one carbon. In the case here, the second element is nitrogen.
     The conclusions result from a computationally intensive calculation of conditions produced in shock waves produced by a comet impact on the earth. The comet is described as a CO2-rich icy body; the source of nitrogen isn't specified in the ScienceDaily article, but it implies that the nitrogen is contained within the comet and was not from our own atmosphere. Comets typically contain ammonia (NH3), carbon dioxide and monoxide, and methane, so perhaps the nitrogen is from the ammonia.
    I've posted a bit about impacts on the Moon, and meteor over Russia here. Here's a bit more on what happens. A typical comet impact velocity is about 50 kilometers a second (112,000 miles per hour!). Comets have a fairly low density (somewhere between porous ice and rocky ice), and they react ("burn") as they descend into our nitrogen-rich atmosphere.  They generate a strong shock wave in the atmosphere, creating a high-temperature, high-pressure blanket ahead of them as they soar to earth.
     Upon crashing to earth, two shock waves are generated. One spreads out into the ground telling the earth, so to speak, that the comet has arrived. The other spreads back into the comet, telling it, so to speak, that it has just run into an obstacle (the comet was already alerted that something had changed by shock waves sent into it during its descent through the atmosphere). A set of conservation equations, known as the Rankine-Hugoniot equations, govern the mass, momentum and energy conditions during the impact. When these shock waves arrive at free surfaces (the rear-end and sides of the comet, the surface of the earth), they reflect as expansion ("rarefaction") waves and these waves eventually reduce the pressures back to ambient.  However, energy is irreversibly deposited in the ground in the form of heat. To first order, the comet is entirely vaporized in the event.
     Goldman and Tamblyn used huge supercomputers at LLBL to solve not only the equations of motion, but equations for chemical reactions during the shock process, to arrive at their conclusions.  These computers calculate reactions at time steps of picoseconds.  Previously computers could only capture 10-30 picoseconds of reactions, not enough time for equilbrium, but with more efficient codes, they were able to run the computations for hundreds of picoseconds, time enough to allow approach to chemical equilibrium. Comets impacting rock at these velocities typically generate peak pressures in the megabar (Mb) range, millions of times our own atmospheric pressure. At these peak pressures, everything vaporizes.
     Of more interest are the chemical reactions in the range of 480-600 kilobars (480,000-600,000 times atmospheric pressure). At these pressures temperatures reach 6,200-8,180 F, and methane and formaldehyde are synthesized. These are known precursors of amino acids and complex organic compounds. As pressure decays in the rarefaction wave, significan quantities of simple, carbon-nitrogen bonded compunds that are known prebiotic precursors are produced.
     At lower pressures, in the range of 360 kb and 4,600 F, nitrogen-containing heterocycles, which can dissociate to form "functionalized aromatic hydrocarbons" in the rarefaction are produced. These are thought to be prebiotic precursors to DNA and RNA base pairs.
     The bottom line is that the "special conditions," such as UV radiation or the presence of catalysts, in many existing models for the origin of life on earth are not needed in this model. It's a simple physical model of chemistry during the impact process.  Some aspects of this may be amenable to experimental testing, and it will be interesting to see the full paper in a few weeks.
   

Why Bobby Jindal was wrong when he suggested abolishing the U.S. Geological Survey: Pavlov and Cleveland volcanoes in action again!

The current eruption of Pavlov Volcano
Photo by astronauts on the International Space Station
NASA

It was 2009, and President Obama had just given a presidential address.  In a widely televised response to the address, Governor Bobby Jindal of Louisiana mocked the volcanic monitoring program of the U.S. Geological Survey as "wasteful spending," and proposed its elimination. Much to the relief of volcanologists and the people in the Pacific Northwest, Alaska, and Hawaii who live near the volcanoes in the U.S., the eruption of Eyjafjallajokull in Iceland the following year, and its huge global economic impact, laid that short-sighted suggestion at least temporarily to rest.

Currently, two of Alaska's most active volcanoes have woken up and are emitting plumes of steam and ash. Pavlov (means "Paul" or "St. Paul" in Russian) became active on May 13. It is part of the Aleutian arc of volcanoes that bound the Pacific Plate on the north side, and it is the most active one. The largest historical eruption of Pavlov took place in 1911 after 5 years of smaller eruptions. The eruption was from a fissure on the north flank of the volcano, and consisted of lava flows and the ejection of large blocks. In this eruption, gas and ash have reached 22,000 feet so far, and ash has been seen to extend downwind for hundreds of kilometers by the astronauts. The volcano is 625 miles southwest of Anchorage. There are 40 known eruptions since the late 1700's.

Cleveland volcano is persistently active, with at least 19 eruptions since the 1980's.  It's current activity consists of single, discrete explosions, of the type often called "Vulcanian" by volcanologists. Some of these explosions have sent ash as high as 35,000 feet.

I have written a short article for "Time Views," to appear on Tuesday June 4 in their on-line edition. In this article, I discuss "chain reactions" that can occur during a geologic event.  In the case of these volcanos, Cleveland at least, has been reported to have sent ash up into the altitude at which modern jet airliners cross the northern Pacific (I couldn't actually verify this with USGS data, but even if it hasn't actually sent ash that high, either of these volcanoes is capable of doing so). Cleveland, particularly, sits right below such a route. The chaos and chain reaction that can be created by volcanoes like these was dramatically illustrated when the Icelandic volcano Eyjafjallajokull erupted in 2011. Air travel for millions of people was disrupted, airlines and some hotels suffered greatly (but others profited greatly), and global commerce was disrupted. Food and flowers, for example, grown in Africa or New Zealand couldn't be flown into the usual markets in Europe, and so both the growers and potential consumers suffered.  In our increasingly interconnected globalized world, we can expect such cascading effects to become increasingly more common.

In fact, Sid Perkins in a ScienceNOW article on September 19, 2011 pondered reviewed a paper published in PNAS that asked what would happen if an eruption like the Laki eruption of 1783 happened today. Four such eruptions have occurred in Iceland over the past 1,150 years, so this is not an academic exercise. Laki produced 122 million metric tons of sulfur dioxide gas, about what humans produce in a year now. One-fifth of the Icelandic population died, tens of thousands died in Europe, and it is likely that the famines that resulted from the weather and short-term climate changes caused by the eruption contributed to political unrest. In particular, there has been speculation that it contributed to the French Revolution. Anja Schmidt at the University of Leeds in the U.K. and colleagues ran climate simulations of a hypothetical eruption under current conditions.**  In the first three months after such an eruption began, aerosols and dangerous particle concentrations would be concentrated over Iceland and northwestern Europe, but also elevated in southern Europe, as much as 60% above normal levels. In the ensuing year, the air pollution would kill an estimated 142,000 people (over the normal death rate). Such an eruption might shut down European air traffic for six months or more, and have a huge impact on European crop yields. These, in turn, could not be replaced because of the shutdown of air and possibly shipping traffic.

And, to return to Bobby Jindal's comment: The U.S. Geological Survey is monitoring the activity of these two volcanoes and, should the intensity of the eruption pick up, will be working with the National Weather Service and the Federal Aviation Administration to find safe routes for those aircraft.

** Schmidt, A., et al., "Excess mortality in Europe following a future Laki-style Icelandic eruption," Proceedings of the National Academy of Sciences, published online before print September 19, 2011, doi:10.1073/pnas.1108569108 PNAS September 19, 2011.