Earthquakes: How Often?

Until the following question arrived, I had only thought of earthquakes as being relatively localized features, mainly occurring along continental margins and ocean-floor spreading centers or transform faults. The San Andreas fault is a mostly on-land transform fault. I hadn't really thought about how MANY earthquakes there are in the world as a whole.

Q:
Hello, I was wondering how many earthquakes happen typically in a year?
-Lauren J

A:

The USGS estimates that several million earthquakes occur in the world each year. Many go undetected because they hit remote areas or have very small magnitudes. The National Earthquake Information Center in Denver, CO, now locates about 50 earthquakes each day, or about 20,000 a year. There are far fewer large events than small earthquakes, and this website will show you how these are parsed out according to magnitude:
http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php

There are lots of fascinating stats here, including an interesting table (below). Like asteroid impacts and frequency, or volcanic eruption magnitude and frequency, these all seem to follow an inverse log law:

The bigger the event, the less common it is.

Frequency of Occurrence of Earthquakes

Magnitude	Average Annually
8 and higher	1
7 - 7.9	15
6 - 6.9	134
5 - 5.9	1319
4 - 4.9	13,000 (estimated)
3 - 3.9	130,000 (estimated)
2 - 2.9	1,300,000 (estimated)

Extinctions: Asteroid Impacts vs. Volcanic Eruptions

The following question indicates that someone was thinking about things - a large step beyond just going to school and memorizing facts.

Q: 
Hello, I am 20 years old and from Portugal. My question arose when studying for school and noticing that these two events happen, more or less if it can be said on this matter, at the same time. Can a major impact like the one at Chicxulub have enough power to send shock-waves trough the mantel causing the major eruption at the Deccan traps? like if you "squeezed" the Earth and at its weakest point it broke, or like when you give a very strong hit on the top of the bottle and the bottom breaks away because of the pressure and strength that traveled until it finds a blockage it has the power to break through ... We know that earthquakes can be felt thousands of miles away but what happens inside the earth on the mantel at that time? If this is correct where would one get proof?
-Diogo C

A:

You have observed an interesting timing association that has intrigued geologists for a long time.

From Wikipedia (http://en.wikipedia.org/wiki/Deccan_Traps): The Deccan Traps formed at the end of the Cretaceous period. The bulk of the volcanic eruption occurred at the Western Ghats (near Mumbai) some 65 million years ago. This series of eruptions may have lasted less than 30,000 years in total. The original area covered by the lava flows is estimated to have been as large as 1.5 million km², approximately half the size of modern India. The Deccan Traps region was reduced to its current size by erosion and plate tectonics; the present area of directly observable lava flows is around 512,000 km2 (197,684 sq mi).

One website (http://palaeoblog.blogspot.com/2011/10/smaller-ka-boom-chicxulub-impact-did.html) offers this observation: "Researchers have simulated the meteorite strike that caused the Chicxulub crater in Mexico, an impact 2 million times more powerful than a hydrogen bomb that many scientists believe triggered the mass extinction of the dinosaurs 65 million years ago. The team's rendering of the planet showed that the impact's seismic waves would be scattered and unfocused, resulting in less severe ground displacement, tsunamis, and seismic and volcanic activity than previously theorized. "

Also from Wikipedia (http://en.wikipedia.org/wiki/Deccan_Traps) is even more specific information about the source of the Deccan Traps: "A geological structure exists in the sea floor off the west coast of India that has been suggested as a possible impact crater, in this context called the Shiva crater. It has also been dated at approximately sixty-five million years ago, potentially matching the Deccan traps. The researchers claiming that this feature is an impact crater suggest that the impact may have been the triggering event for the Deccan Traps as well as contributing to the acceleration of the Indian plate in the early Paleogene. However, the current consensus in the Earth science community is that this feature is unlikely to be an actual impact crater."

The short answer is that the Deccan Traps probably did not cause the extinction that wiped out most of the non-avian dinosaurs, though it may have contributed to making life even more difficult. There appears to be no connection between the Deccan Traps and the Chicxulub event.

On a related tack, the even larger Siberian traps (http://en.wikipedia.org/wiki/Siberian_Traps) formed 250 million years ago, and may have contributed to or even caused the Great Dying, the Permian-Triassic extinction event, the most complete extinction event in Earth's history. More than 90% of all species living in the Permian era abruptly disappeared at this time.

~~~~~

Coral Reefs as Resources

The US Geological Survey expends a lot of time and manpower on resource estimation: energy, minerals, biological (in several ways). The following question came at me sideways, and caused me to really think.

Q: 
What are some resources that coral reefs provide?
What are some topographical features around coral reefs?
- Maya R

A.
The main resources that coral reefs provide - that most people talk about at least - is biodiversity. This is a hard thing to quantify or explain, but if reefs all die from acidification and heat related to climate change, then much of the food-chain in the oceans would be severely disrupted. Some new drugs have already been derived from unique reef species, so that is another potential future resource. I believe that there are some entities that have mined reefs for the calcium carbonate that they contain, but this is like the Spaniards four centuries ago melting down precious Aztec and Incan gold artifacts. Trying to capture a "resource" this way destroys 95% of its value.

Coral can only grow where there is light, so this generally means the fringe waters of islands and coastlines, and only in tropical latitudes. In the Pacific, this often means that there are reef rings around volcanic islands or below-the-surface guyots. As the original core rocks of the volcanic island weather and crumble down, this generally means that the remaining topographic feature is an atoll: a coral ring with a shallow lagoon inside. There is very little topographic relief above the water line. The topographic fall-off of an island reef system tends to be steep, however. I've Scuba-dived some of these and the reef "wall" looks like it just goes straight down into the black depths. There are also reef systems on continental margins, and the Great Barrier Reefs of Australia and Belize are examples. Bathymetry tends to follow this characterization as one moves outward: the continental margin, then shallow water, then a reef system, than a steep fall-off to the continental shelves or in some cases the oceanic abyssal plain.

~~~~~

Rock Classes - from the forthcoming book "Ask a Geologist"

Rocks can be generally classified into one of three general rock classes. The first two of the three classes are easy to recognize:
1. Sedimentary rock, formed in layers by the accumulation of weathered rock fragments and/or chemical precipitates, usually under, or under the influence of water (and sometimes wind),
2. Igneous rock, which includes volcanic lava, as well as related (coarse-grained) intrusive rocks such as granite, diorite, and (the usually-very-dark) gabbro.
3. Metamorphic rock. This is generally more difficult to characterize and understand because it is modified – a derivative of - one of the other two.

About 90% of the queries we receive on Ask-a-Geologist, typically accompanied by a photo and asking "what is this rock", we cannot usually answer. In general, the photos have no scale and are blurry, and the light doesn't show the finer structures well. A geologist would want to turn the rock sample over in sunlight with a hand-lens, looking for mineral grains and their distinctive crystalline form or "habit", and perhaps scratch visible crystals with a knife-blade to check their hardness to aid her identification effort.

The following is a rare case of a query accompanied by a good quality photo (it even had a coin to provide scale!) and enough additional context information to allow me to identify the rock.

Q:
Last weekend I climbed Mount Mansfield in Vermont. The higher we got, the more silvery the rocks looked. Attached is a picture, but it doesn't really do justice to the silvery tone. My friend wanted to know what caused the rocks to look so silvery.  I said I'd ask the expert.
--Valerie W

A:
That's a schist. As in, that's a Gneiss Pile of Schist.  ;=)

Bear with me here – there is a point to this.

The silvery-ness that you see is caused by metamorphism, that is, a change to the character of the rock and its inclusive minerals. The word derives from metamorphosis – literally, change of form. Metamorphism usually is caused by the original igneous or sedimentary rocks being buried by tectonic forces at some time in their ancient past, but it could also be caused by hot fluids from a nearby heat-source (like an intruding granite body). Old-time miners would say that metamorphic rocks had been “stewed and cooked” – which is remarkably prescient.

The deeper a rock is buried, the greater the consequent increase in pressure - and also temperature – that it will experience. The photograph shows a complex rock that under great pressure has been deformed plastically – in this case, it is a schist. According to several sources (here's one: http://en.wikipedia.org/wiki/Blueschist ) this means depth of burial at one time reached 15 - 30 km before it was uplifted by tectonic processes and then exposed by weathering. The result of this high pressure/high temperature transformation process is that the original minerals are converted into several new minerals in a schist, commonly including glaucophane and muscovite - the latter is usually called white mica. Typically, there is plastic flowage going on, which leads to the alignment of the glaucophane and muscovite in the flow direction - and you can see this in your photo. The muscovite in these rocks, however, is usually very fine-grained - sometimes not easily visible even in a hand-lens. The net effect is to give the rock an over-all glossy look, and if you ran your hands over it, a slightly greasy feel sometimes. By the way, there are blueschist (blue-gray in color) and greenschist varieties of this rock. The latter are prominently greenish in color, because this kind of schist is loaded with chlorite and epidote: green, chlorine-rich minerals both derived from original black minerals such as pyroxene, and dispersed throughout the resulting rock as a whole by the metamorphic (“stewing and cooking”) process.

You describe the rock becoming more silvery with increasing elevation. That could be because the entire mountain is upside down from its original emplacement, and as you rise in elevation you are in fact walking deeper in time and burial depth. While this sometimes happens during tectonic processes, it is not very common. Though it seems more deformed, I suspect that in fact you are seeing a gradational change from an even more strongly metamorphosed rock, called a gneiss, found at the lower elevations of your hike. This kind of rock does not have the muscovite “sheen”, but instead is typically devoid of chlorite and platy minerals. Gneiss commonly has much larger crystals - this is because the rock was so hot, and maintained for such a long time a great depth of burial, that everything re-crystallized. The longer a hot, fluid mush is held in place, the larger the crystals can grow. Gneiss is typically formed at 15-50 kilometer depths. I suspect that the original rock mass is still more or less upright, and that you were in fact climbing up from deeply metamorphosed gneiss to less-metamorphosed schist above it.

~~~~~

Mount Lemmon is a spectacular uplifted mountain range located far to the south and west of Mount Mansfield - it lies just north of Tucson, Arizona. From the city, the face of the mountain has the broad texture and layering of the original sedimentary rock that it was made out of. However, up close it is coarsely crystalline and very much NOT (any longer) a sedimentary rock. As you move farther north in that complex you are moving ever deeper in original burial depth, and the gneiss turns gradually to granite – back to an original plutonic form. The original sediment probably was weathered out of a nearby, much more ancient granite complex. There is a famous story of a PhD student (Dr. Ed McCullough, who eventually became the geology department head at the University of Arizona) finding a blastoid (head) of a Paleozoic crinoid in the metamorphic rock while mapping the complex with other faculty. This story – and Mount Lemmon - neatly tie all three rock types together in one package.

~~~~~

He Should Have Known

What do Baitullah Mehsud, Osama bin Laden, Anwar al-Awlaki, and Isoroku Yamamoto have in common?

Eleven years ago today, I was chairing a conference on unusual applications of geophysics at a large geophysics convention in San Antonio, Texas. I had just given the keynote talk in a room with about 1,500 people in it when my co-chair, Chris Liner, handed a piece of paper to me. His hands were shaking. It said that “planes had hit the World Trade Center and both towers had collapsed”. This did not compute with me: they were HUGE towers. A small plane had crashed into the smaller Empire State Building in the 1930’s and just stuck in the side. Chris asked me what we should do? I stood up and announced to the audience what we had just read, and said that the session would continue - but for people with family in that area to please feel free to step out and try to get in touch with them. I then excused myself, and after 9 tries finally connected with Louise, and learned that it was a lot worse than I had thought. She was still trying to get out of Washington, DC – her office was a block and a half from the White House - and had been walking in huge crowds for 2 hours already. She now considers the passengers on Flight 93, who forced down their aircraft near Shanksville, PA, as saviors. 

The rest of my story is like most other peoples’: After three days of staring at the Trade Towers collapsing over and over and over again on TV, I bought an American Flag tie, and took a taxi to the airport for my flight home. I soon realized that I was not going to be able to fly home. I walked out to the Hertz desk and the agent kindly offered me a car, said there would be no drop-off charges, and I started driving. It took me seven hours just to get out of Texas. Every two hours I would get a call from my Palestinian-Saudi son-in-law… who was worried about me. I was worried about him. No, people were not giving Hamed a bad time, in fact if anything they were being overly-protective of him in his home town of Charlotte, NC. The phone-calls depleted my phone battery, however, so I stopped in a Radio Shack to get a car-charger, and struck up a conversation with a police officer. We talked about our respective training in dealing with people wielding knives. Neither of us could believe that people were cowed by half-inch box-cutter blades into being passive sheep and waiting to fly into a building. “THAT’s not even a KNIFE!” he said, angrily.

I was full of anger. It kept me awake for 20 hours, until I finally stopped in eastern Tennessee, figuring I was probably becoming a danger to other people on the road by now. That anger got me all the way home – but then it stayed with me. How DARE someone take advantage of and then abuse our national hospitality to attack us, murder nearly 3,000 innocent people, for…what? Salifist jihadism? Why was it so important to be like the Old Ones (what Salafi means)? What could possibly make it important enough to murder 3,000 innocent people? There are harsh words for people who murder innocents - right in the Qu'ran. 

Before anyone attributed the truck-bomb attacks in Kenya and Tanzania in 1998, the name “bin Laden” came to my mind. I had probably walked past him in the late 1970’s in the souq in Jeddah, Saudi Arabia. I fancy that I had seen a tall, slack-jawed young guy who wore the red-and-white Saudi style shmaugh on his head but without the black aighal to keep it in place - to be just like the prophet Mohammed. I had camped with my children in the Asir region, the high scarp mountains of western Saudi Arabia, where 11 of the 19 hijackers had come from. I had seen the hatred in the eyes of the aighal-less Muttawah, aimed at me, a non-muslim. These religious police gave me and my family looks that could kill, as they herded unwilling young men into the mosques at prayer time. I couldn’t comprehend that hatred then, and I don’t understand it now. 

For years, however, the ‘righteous anger’ stayed with me. I would clip out news headlines that had anything to do with bin Laden and 9/11. I have a stack in the map-drawer in my office. I read every entry in The Long War Journal, memorizing names, keeping track of all the 3^rd-in-commands in al-Qaeda who seemed to last about two months on average. Ah… they finally popped the murderous Beitullah Mehsud with a Hellfire missile. Al-Awlaki was another one of those persistent, "Let's you and him fight" kind of guys, but he met his own Hellfire last year, not long after the SEALS shot bin Laden in the eye.

Yesterday I was reading “No Easy Day,” about the Navy SEAL team who flew to Abbotabad, Pakistan, and in 35 minutes assaulted bin Laden’s compound and then flew his body back to Jalalabad, Afghanistan. Two things stuck out to me: (a) how quick and efficient - and inexorable - the assault had been, and (b) that bin Laden encouraged thousands of people to commit suicide, to become shaheed, martyrs. A rather large percentage of these martyrs have been 12-to-14-yr-old boys. Someone else's children. But when the SEAL’s assaulted his compound, he was the only male present who did not take up a weapon and try to fight. He never touched his AK-47, nor his Makharov. They were found in easy reach, but not even loaded. When it came down to it, bin Laden didn’t have the courage to man up to what he had preached to his poor followers.

The anger finally left me.

How does Yamamoto figure in the title? Isoroku Yamamoto (1884 – 1943) was a Naval Marshal General, the commander-in-chief of the Japanese Combined Fleet during the decisive early years of the Pacific War, and was thus responsible for major battles such as Pearl Harbor and Midway. He died during an inspection tour of troops in the Solomon Islands when his aircraft was shot down during an ambush by American P-38 Lightning fighter planes. His death was a major blow to Japanese military morale during World War II.

He should have known.

Yamamoto was not a bad man. He had opposed the invasion of Manchuria in 1931, the subsequent colonization of China (1937-45), and the 1940 Tripartite Pact with Nazi Germany and Fascist Italy. As Deputy Navy Minister, he even apologized to United States Ambassador Joseph C. Grew for the bombing of the USS Panay in December 1937. These issues made him a target of assassination by pro-war militarists. In 1924, at the rank of captain, he was part of the Japanese delegation visiting the U.S. Naval War College. Afterwards, he toured the industrial heartland of the US. When the militarists forced the confrontation with the United States, which by then was embargoing fuel oil supplies to stop the expanding imperialism in China and southeast Asia, Yamamoto argued that they would awaken a sleeping giant. He said that Japan would not win this war. His argument did not prevail, of course. However, he was right in the end.

Anwar al-Awlaki, like Yamamoto, had spent time in the United States, had been welcomed, treated with courtesy. Like Yamamoto, he should have known. Bin Laden had spent a large part of his waking hours from 1996 onward studying the United States. This was the country that had landed a man on the Moon, and later obliterated the 4^th largest army on the planet – on the other SIDE of the planet – in just two weeks in 2003.

He should have known. 

~~~~~

Tsunamis, Rogue Waves, and Tidal Waves

Geology started out as the science of uniformitarianism: What we could see in the rock record is what we could expect to see in the future. The initial assumption of Lyell and other early geology pioneers was that the “Great Flood” of the Bible was not to be taken seriously, and that every geologic phenomenon in the past was like what we observe today: calm and steady and slow – like weathering.  However, in the past several generations, geologists have come to recognize that there have been short-lived, phenomenally catastrophic events that have changed the face of the landscape. One of these is the tsunami, a word of Japanese origin where it was first described scientifically. The word was chosen about a generation ago to distinguish one kind of wave event (a tsunami) from a tidal wave or a hurricane storm surge. A tidal wave is a twice-daily feature associated with Lunar and Solar cycles. In Southeast Alaska and the Bay of Fundy in eastern Canada, these can reach 15 meters in height – especially if focused into an east-west-oriented narrow bay or fjord such as at Fundy. A “tidal bore” is a wave that moves in with a rising tide, and in shallow estuaries like Turnagain Arm in Southeast Alaska, these can be walls of water several meters high – sufficient to overturn or “pitch-pole” a medium-sized boat.

Q:

What causes tsunamis? Can one happen in the US?

-Jared W

A:

There are four different kinds of events that have caused tsunamis in the past:

1.       Asteroid impacts. There are huge tsunami deposits on Haiti stemming from an asteroid impact 65 million years ago.  This was the dinosaur-era-ending Chicxulub asteroid, which impacted on what is now a small village of that name on the northern tip of the modern Yucatan peninsula of Mexico. Fragments of this explosion apparently also went sub-orbital and landed as far away as Montana and the mid-Pacific ocean. Estimates of a mega-tsunami wave in the Caribbean up to 3 kilometers in height have been suggested – enough to completely inundate a large island such as Madagascar.

2.       Landslides. The face of a mountain fell off into Lituya Bay in southern Alaska in 1958. It created a wave at least 500 meters high, judging from surrounding mountains stripped of trees to at least that elevation. Surviving witnesses describe their vessel being floated over a large raft of logs, and the modern coastline remains largely denuded. http://en.wikipedia.org/wiki/Megatsunami

3.       Volcanoes. When the volcano Krakatau exploded in 1883, 45-meter-high waves reached as far as 10 kilometers inland on Sumatra, and swept people, animals, and debris back into the Sunda Strait. More than 36,000 people died in this event, and contemporary descriptions report that a person would walk across the Sunda Strait on bodies and logs without getting their feet wet. http://www.csmonitor.com/World/Global-Issues/2010/1028/Japan-tsunami-is-small-compared-to-five-of-world-s-biggest-tsunamis/1883-Krakatoa-tsunami The tsunami from the catastrophic eruption of Thera volcano (modern Santorini in the Aegean) 3,500 years ago apparently ended the Minoan civilization on nearby Crete. The language of modern science is substantially Greek-based (with Latin) as a result of that single event.

4.       Earthquakes. In January 1700 AD, a subduction earthquake in the Cascadia region of northwestern North America sent a tsunami across the Pacific Ocean that devastated villages on the Sendai coast of Japan. The earthquake sunk a forest in Puget Sound below sea level. The wave that reached Japan was called the “Orphan Tsunami”, since it was not associated with any locally-felt earthquake or typhoon – it arrived without warning under a clear blue sky. In 1946 a subduction earthquake off the Chilean coast of South America caused what one geologist friend referred to as “unplanned urban renewal” many hours later in Hilo, Hawaii. I have personally seen signs marking the wave run-up on telephone poles 5 meters above my head in the modern downtown area. The Great Sumatra Earthquake of December 2004 killed over 250,000 people from Indonesia to India. The wave reached Sri Lanka many hours after it was initially triggered, but there was no infrastructure in place at the time to warn the millions of affected people in its path. The Great Tohoku Earthquake of 2010 triggered a tsunami that devastated northeastern Japan, directly led to a melt-down at the Fukushima Dai-Ichi nuclear plant - and destroyed docks and ships many hours later on the Oregon coast.

It is important to understand that relatively few earthquakes cause tsunamis. The basic requirement is that the causative fault must have a normal or reverse component to it - part of the seafloor must drop or lift suddenly. Modern tsunami warning systems are based on a two-tiered approach: an initial earthquake beneath an ocean floor or ocean margin is detected. If the fault system is well known (for instance is understood to be a subduction fault), then an initial warning is issued. Deep ocean buoy systems are then monitored – these waves may travel at more than 500 kilometers per hour, so they take a relatively long time to cross an ocean. If a wave-front is noted passing through this system, then warning sirens light up on the threatened coast. http://en.wikipedia.org/wiki/Tsunami_warning_system

Technically, hurricanes (Atlantic Ocean) and typhoons (Pacific Ocean) do not cause tsunamis, but they DO generate low-pressure-driven storm-surges that could top 10 meters above normal sea level in the worst cases. These are not sharp-edged waves like a tsunami, but instead are long-wavelength, very broad surges of seawater tracking the eye of the hurricane or typhoon as it hits land. Hurricane Katrina in 2005 did most of its damage with a huge storm-surge that overwhelmed the levees and barriers designed to protect New Orleans, a city that over time since its founding has sunk below sea level.

There is another class of large water waves called “Rogue” or “freak” waves. There is a long history of “disappeared” ships in the history of humankind, and anecdotal stories of waves exceeding 30 meters in amplitude that somehow left survivors. Recently, sea-height-measuring radar satellites have allowed this sort of feature to be quantified. The physics concept of constructive interference of waves comes into play, but there may also be other factors involved, including diffractive focusing and non-linear effects. For instance, the southwest-flowing Agulhas current in the western Indian Ocean has long been known to interfere with westerlies to create a zone of dangerous rogue waves of unusual frequency and intensity.  http://en.wikipedia.org/wiki/Rogue_wave

By the way: that Biblical story of the Great Flood? As scientists we must be careful and not just dismiss something out of hand - like this one was. Geologic evidence now suggests that the Black Sea was a huge, populated continental basin that flooded catastrophically around 5,600 B.C.E.  

- due to waters from the Mediterranean Sea breaching a volcanic sill in the Bosporus Strait.

~~~~~

Get the Data. Don't get Killed.

There are different risk-factors that come with different life-callings:

• Fish for King Crab in the Barents Sea: unusually high risk of becoming crab food.
• Transport cocaine from Colombia to Texas: unusually high risk of being beheaded.
• Fight forest fires: unusually high risk of joining the Bar-B-Que and burning with the trees.
• Work as an accountant: Live Long and Prosper!

There have been several questions directed at us about safety while working as a geologist or geophysicist. These increased, as expected, during the 2004-2006 eruption of Mount St Helens. In a previous response to a question, I mentioned walking out the leading edges of moving lava flows in Hawai'i. This was not done casually, but to gain a clearer understanding of how these flows move - and why they suddenly can inundate towns like Kalapana. If we understand how lava creates its own new topography, perhaps we can predict where the Danger Zones are. 

This has non-trivial real-world consequences: if you build in Zone 1 or Zone 2 your home-owner's insurance will be phenomenally high, if you can get it at all.

In a larger sense, however, this opens the broader issue of inherent risk that comes with certain jobs - and how you can manage those risks.

In 1977 a young USGS geologist named Cynthia Dusel was part of a mapping team, surveying the Big Delta Quadrangle in east-central Alaska, when she was attacked and mauled by a bear. She survived, but lost both arms. Since then she has married, had a son, and even served as acting chief of the Western Mineral Resources team in Menlo Park, CA. She's something of an icon among us in the USGS: very matter-of-fact about her disability, very upbeat, great sense of humor - and epitomizes indomitable courage. 

The response to that attack within the USGS was probably predictable: everyone going up to work in Alaska started packing huge guns. Then the scientist in the Survey scientists stopped and many of them thought about it a bit more. Let's gather data about the real threats to geologists working in Alaska! they said. They did... and were surprised to learn that bear attacks came in as Number 7 on the list. Shooting yourself with your own weapon came in Number 3 - and this led to the development of a sophisticated 3-day weapons safety training course (informally called the "Bear Blasting" class) required of anyone planning to work in Alaska. Number 2 was helicopter accidents - my first USGS boss was killed in Ketchikan harbor this way. And this led to careful "carding" of pilots and mandatory training of geoscientists, so that none of us ever worked with a pilot with less than 5,000 hours of flight experience, for instance.

Number 1 was drowning. That's right: drowning. If you fall into deep water in Alaska (and southeast Alaska and the Aleutians are mostly islands, anyway), your arms will essentially stop working after about a minute unless you are wearing a Mustang suit. That's hypothermia for you. I came within a hairs-breadth of becoming one of those drowning statistics in Klawock in 1995.

It became a growing part of our scientific tradition: we all loved working in the field, but it carries with it different dangers. Soooo... how can we minimize these? How can we manage these risks?

Q:

That's a pretty crazy account.  It's particularly funny to think about your work when I think of it in comparison to our OHS (occupational health and safety) officers who come around to inspect our offices periodically to make sure that our chairs are properly aligned to make sure that we don't hurt our backs by sitting all day long.  Why in the world would you be stomping around an area of jungle amidst fresh-flowing lava?  - Lisa W.

A:

Throughout my professional career I've faced many rather disparate dangers. This wasn't done for the adrenaline thrill - it's the only way in most cases to acquire the crucial data that we need to solve real world problems. In the Continental US, this usually means working in really rugged terrain. I camped overnight with a geophysical crew inside the crater of Mount St Helens in 2007. I had helicoptered in with some geophysical equipment, but after several days had to get back to the office before the end-of-week scheduled helicopter flight. A case in point: I planned for it, and walked out. However, it proved to be far more rugged terrain than I had anticipated in my planning (which was done with 10-yr-old air-photos in a terrain that is unconsolidated, and evolving nearly every day). If I had not been carrying (and using) hiking poles with my pack, I wouldn't be wearing these front teeth today. I still sustained permanent damage to my left big toe and my right knee in the ~20 km walk-out (the knee is still swollen as I write this).

In Venezuela, my personal journals have WAY too many "I was nearly killed again today" entries. That was the first time I really looked at the full array of danger that comes with working in the deep jungle. Initially we went down for a three-year assignment to map the roadless, jungle-covered southern half of Venezuela thinking the the big risk was from snakes. In fact, I encountered a Bushmaster on my very first Entrada. It took awhile to recognize the more subtle, even hidden dangers: testosterone-poisoned pilots, poorly-maintained helicopters, Chagas disease, piranha in all the rivers, etc. The Number 1 killer? The Anopheles mosquito - the vector for Plasmodium Falciparum, also known as cerebral malaria, followed closely by drunk drivers. I lost two of my best friends in Venezuela, in separate incidents, to drunk drivers.

After a series of very close calls I took the Advanced Trauma Life Support training at the University of Maryland medical school (yes, it's supposed to be for medical doctors - but I have the certificate to prove it). I discussed the issues with some more experienced field geologists and began instituting some safety protocols for the mapping mission that I was in charge of - for instance we almost never used helicopters after the first year there. We wore light-colored clothes to minimize being targeted by Africanized bees. We always walked the picas (trails) in pairs. We always insisted on mosquito nets surrounding our hammocks, etc. One of my colleagues instituted one safety protocol himself: he bailed out, breaking his contract and leaving his commitments on my shoulders. I've never begrudged him for this by the way: he was one really, really frightened dude. A year later he even left the geosciences profession, abandoning his PhD training, to become a financial advisor. Live long and prosper.

But here's the thing: you CAN control the variables, you CAN push the statistical envelope far over to the likely-to-survive side of the Gaussian probability curve. 

I took some training last year that is a case in point. You can't study a volcano unless you can get a lot of equipment up INTO it. My sons will attest that just getting 300 kilos of gear up into the Pumice Plain (the Mount St Helens Blast Zone) for their mom's Masters Degree research project was a non-trivial exercise. It's much harder to do this in the upper edifice of the volcano - so we use helicopters.

Easy to say, technically hard to do.

The safest way to ensure the survival of the helicopter and pilot is NOT to have a lot of loose shovels, antennas, and batteries INSIDE the ship. This little nugget of wisdom was culled by carefully gathering reports of all helicopter crashes in the United States over 50 years. Instead, you *sling* all that loose, sharp-edged junk. There is an electrically-controlled hook on the belly of most helicopters. We took a full day to practice this routine on a level lawn:

• Gather all your gear in a pile, weigh it piece by piece. Give that manifest to the pilot - who will do a calculation to see if he can even lift it to the elevations you will work at AND have enough margin to carry you along with it.
• Load it into a net that itself weighs 25 kg. Try to balance that net, arrange it so things tilt inward, and especially be sure that nothing is sticking out of the net that could tangle with anything - like you, or the skids.
• Then call the helicopter in to you, holding your hands up and out in the direction of the wind (we usually dangle a strip of red flagging tape so the pilot can judge the local wind velocity).
• As the ship approaches, it comes in slowly at about 1.5 meters off the ground - remember that the thing is wobbling around in the wind as the pilot tries to control it against the volcano-heat-triggered turbulence, and it is SCREAMING SO LOUDLY that you can easily get rattled just by the 140-db sound (we wear helmets with ear protection, but it's still unnerving).
• You must then walk under this shuddering, screaming thing, hook your sling net to the belly, and then carefully back out (NOT turn around), without tangling your feet in the net, and keeping your footing amid the rocks and talus.
• Above all, if you stumble, you must NOT grab one of the skids to regain your balance. If you do, the ultra-light craft will flip, the blades will hit the ground, and all that angular momentum must go somewhere really, really fast – and you will both probably die. You have to trust the pilot, and he must trust you: if you hook the net wrong, or inadvertently tangle it in one of his skids, it could kill him. The craft is so fragile that you can literally push it around in the air above you with your hand... but those screaming turbines mean it is powered by 600 horses. Everything spinning is so finely balanced that if a blade nicks a branch it will chip a chunk off – and it then becomes hugely unbalanced. Then the angular momentum comes into play, and the aircraft will literally beat itself (and its occupants, and everyone within 20 meters) to death.

When a helicopter goes down, that's just the beginning of the bad stuff... think of the old high-school joke: What's red and green and goes round and round real fast? A frog in a blender. Now imagine doing this sling exercise on a steep ridge with 30-knot wind gusts.  THAT's why we practice and practice all day long on a lawn to do this right. So it's reflex.

Live Long and Prosper. And still enjoy the Adventure!

~~~~~