Tuesday, December 31, 2013


Anyone who has read 3 Nephi 8, especially if they are aware of some of the details of Mount St Helens' 1980 eruption, have pondered expressions such as "...there were exceedingly sharp lightnings...", "...the city of Moroni did sink into the depths of the sea...", "...the whole face of the land was changed...", "...there was darkness upon the face of the land...", and the "...the inhabitants thereof who had not fallen could feel the vapor of darkness..." that engulfed the Nephites nearly 2,100 years ago.

Central America, of course, is an integral part of the Pacific Ring of Fire, so-called because of the string of volcanoes that all lie just inland from the Pacific Ocean margins. The Ring includes hundreds of volcanoes, among them the huge Cerro Hudson in southern Chile, Masaya in Nicaragua, Shasta in California, Mount Rainier in Washington, Mount Edgecumbe near Sitka, Alaska, and Kenai and Veniaminof, the monster volcanoes of the Aleutians. Farther east, on the other side of the Pacific Ocean, the Ring of Fire includes Bezymiani, Sheveluch, and Mutnovski-Gorely in Kamchatka, and Alaid and others in the Kuriles. The Ring includes Usu, Fuji, and Sakura-Jima, the best-known volcanoes in Japan. We can't leave out Mount Pinatubo in the Philippines, whose 1992 eruption lowered the world wide temperature by two degrees centigrade, and we must include the long arc of volcanoes in Indonesia, including the monster Toba. The phenomenal eruption of the Toba supervolcano around 72,000 years ago may have reduced the proto-human population on Earth to as few as 2,500 individuals.

All these volcanoes (except for Indonesia) lie just inland of the Pacific Ocean margins because they lie just above their sources: the down-going Pacific Ocean seafloor that is being over-ridden by continental margins all around it. Linking the over-riding continental plates with their subducted oceanic plate are huge subduction faults. These are the sources of the largest earthquakes in Earth's recorded history, including the magnitude 9.5 Valdivia earthquake of 1960 in Chile (whose tsunami destroyed downtown Hilo, Hawai'i, about 8 hours later). Other subduction earthquakes include the magnitude 8.7 to 9.2 Cascadia event of 1700, which sank an entire forest in Puget Sound, and whose "Orphan Tsunami" destroyed villages on the Japanese east coast. The magnitude 9.0 Tohoku Earthquake of 2010 triggered the meltdown of the Fukushima-Di-Ichi nuclear plant and devastated the northeastern Japanese coast. The huge magnitude 8.6 Aceh subduction earthquake of 2004 created a tsunami that killed at least 250,000 people along the Indian Ocean margins.

During the Spanish era, regional Central American capitals such as Santiago de Guatemala and Nicaragua, Honduras, were repeatedly destroyed and rebuilt. To say that earthquakes and related volcanic tephra-falls changed the face of the land in Central America would be an understatement.

Since the 1963 eruption that created the island of Surtsey, Iceland, and the 1980 eruption of Mount St Helens, volcanologists have known that lightning storms are closely associated with Plinian eruptions. This is because of the vast electric charge lofted along with the prodigious amounts of volcanic ash that are transported to the stratosphere.

But what caused the "vapor of darkness" described by Nephi? This was almost certainly a smothering blanket of volcanic ash. Mount St Helens, 1980, was a relatively small (VEI 5) eruption. It lofted about 3 cubic kilometers of material, and left nearly a meter-thick blanket of ash in Yakima, Washington, 244 kilometers to the east, within a few hours of its eruption.

To get a handle on a smoking gun for 3Ne:8, we must examine the largest volcanic eruptions in Central America. One way to do this is to accumulate information on tephra falls that reached out great distances - the larger the reach, the greater the eruption. Two events stand out:

  • Masaya volcano, Nicaragua, about 2,100 years ago, left tephra as far as 170 km distant.
  • Chiletepe volcano, Nicaragua, about 1,900 years ago, left tephra as far as 570 km distant.
Note that these dates are somewhat approximate (they come from Kutterolf et al, 2008, Geochemistry, Geophysics, Geosystems). The Masaya eruption lofted approximately 8 cubic kilometers of ash and tephra, nearly three times more than Mount St Helens. Interestingly, ancient human footprints have been found at Acahualinca - these are 2,100-year-old fossils discovered along the shores of Lake Managua, Nicaragua, frozen in the volcanic ash from Masaya. Both these volcanoes lie eastward of the subduction zone where the Cocos Plate is being over-ridden by the Caribbean Plate at a rate of nearly 7 cm/year. This rate is nearly three times faster than the Cascadia subduction rate, which means that there are proportionally more frequent earthquakes and volcanic eruptions in Nicaragua than in Washington and Oregon. 

I'm just struck by that name: Masaya. 


Friday, December 27, 2013


For Bilbo Baggins, an Adventure made life worth living.

For many human beings, adventure is often just being able to claim you were that first at something: the first on a new pitch at Smith Rocks, Oregon, the first to summit K2 in Nepal, the first to free-climb Half Dome in Yosemite...

There are several books at home that I cherish, including

  • "Undaunted Courage" - the Lewis and Clark expedition,
  • "Sailing Alone Around the World" - Joshua Slocum's first one-man circumnavigation of the Earth,
  • "Tigrero" - Alexander Siemel's hunt for man-eating Jaguars in Brazil's Matto Grosso,
  • "Endurance" - Earnest Shackleton's Antarctic expedition and Worsely's incredible navigation across 800 miles of the terrible Southern Ocean to South Georgia Island.
There are others, but these are the ones I re-read every couple of years.

I have pondered a definition of "Adventure."  In my opinion it means going off to someplace where few if any have gone.  It does NOT mean a day-trip, or going somewhere that a cell-phone can call for help from. Importantly, it means going someplace where you are on your own.  If something goes bad, it's up to you and your expedition members to work out your own survival. Fail, and there is no record of the fact that you perished - or like the Franklin Expedition to seek the Northwest Passage, archeologists reconstruct your grim demise a century later. 

According to this definition, I and many of our family members have had some adventures:

  1. My first, 10-day sojourn in the deep Amazonas forest of southern Venezuela. It was full of amazing wonders, but I nearly died.
  2. Jared, Val, and I hiked to - and summited - Mount Roraima ("The Mother of Waters") on the Venezuelan, Guyana, and Brazilian triple-frontier. The trip covered over 50 kilometers on foot, and the last pitch required climbing a crack up a 700-meter (2,000-foot) cliff to an eerie Moonscape at 3,000 meters (9,600 feet) elevation.  Wearing T-shirts, we were promptly engulfed in a sleet-storm. 
  3. Louise and Lisa made that same trip the following year - Lisa wore flip-flops most of the way.
  4. Louise and Val hiked to the great Auyantepuy - the greatest cliff-sided mountain on Earth - and climbed it - and both nearly drowned in Devil's Canyon on the way.
  5. My first trip into the roadless Amazonas Territory of southern Venezuela. I was nearly consumed by insects on this trip, but the real sticker was an encounter with a pair of murderous bandits... who counted us at least three times before they decided there were too many of us (about 20) to cleanly kill. Our Venezuelan counterparts also reminded the bandits that we were American diplomats - and there would certainly be follow-up if we didn't return. 
  6. The first Summer Crossing of the Empty Quarter (there are only a handful of true crossings on record). This required driving 1,700 kilometers (over 1,000 miles) over continuous sand dunes in the hottest desert on earth - even Bedouin only venture into the fringes, and only in winter. Neither fixed-wing nor rotary aircraft can venture into this desolate place; we had only intermittent HF radio contact with the outside world. We camped one night in northern Yemen during its 1994 Civil War - because the Saudi border map placed one guard-post fully 72 kilometers (45 miles) from where it actually was. I completed a magnetic survey over an asteroid-impact site called Wabar when the temperature reached 61 degrees C (142 degrees F) - and according to my companions, was unconscious for 20-30 minutes from heat-stroke afterwards. The next day we visited a "weather station" that was so radioactive that my Geiger Counter went off-scale at its highest setting when my back was against the outside wall.
  7. The first overnight camping expedition inside Mount St Helens volcano, just as the 2004 - 2006 eruption was ending. I did this to help a crew of desperate geophysicists, but unlike them I chose to walk out, and not take the return helicopter. This meant hiking in incredibly-dissected, unconsolidated boulder fields for nearly 20 kilometers with a 30-kg backpack. I lost a toe-nail and blew out a knee doing it, and no, there was no cell-phone reception. 

I have cherished photos of these trips, and the book Louise and I wrote about Venezuela has 45 photos in it, many from other-worldly Mount Roraima. We made many more wilderness trips, but in most (but not all) cases we had cell-phone or sat-phone access in case of an emergency.

But here's the thing about adventure: there is the up-side (the excitement, the discovery), but there is also a downside: danger, perhaps death. My personal journal while in Venezuela is full of annotations like "I was nearly killed again today..."

If you push the statistical envelope by doing this too often, You. Will. Die.


Sunday, December 22, 2013

Earthquakes only during the day?

According to my calculations, the 6th grade means students are around 11-12 years old. If so, then the Rising Generation is full of people a lot smarter than I was at that age. The question below from Ask-a-Geologist is just one of many like it:
Q: Dear Geologist,

Our name is Arianah and Cray and we are sixth grade students at Preston Middle School in fort Collins, Colorado. We are currently learning about how the Earth’s surface changes over time. We are curious about earthquakes. We have a couple questions for you. Is there a common time when earthquakes happen during the day? Also, why did you become a geologist?

Yours sincerely, Arianah and Cray :D
1. Earthquakes are essentially random. We understand why they happen, we understand where they happen, but we do NOT understand WHEN they will happen. There are always aftershocks following a main event, of course, but the main event cannot be predicted. Extensive research has shown that there is no correlation between earthquakes and certain times of the day or external * events - for instance there is no correlation with either the location of the Sun, or of the Moon, or with tides (alignments of celestial bodies, which cause neap tides or spring tides, is called syzygy). Some of the brightest minds on this planet have been searching for more than a half century for some evidence that main event earthquakes can be predicted, but without success. They can be forecast #, but not predicted.
2. I was a solid-state physicist and realized that if I didn’t do something drastic, I would be stuck inside a laboratory all my life with radioactive sources and high-pressure cells. This was brought very much to my attention one day when I had a high-pressure cell blow out and spew Cobalt-60 all over the inside of our lab, and had to call in a special Spill Team. Also, by this time physics as a profession was drifting into a dead end with string theory, and I saw relatively little value to humanity to spending billions of dollars to see if another exotic particle existed. I checked out break-offs of physics, including astrophysics, hydro-geophysics, weather physics, and geophysics, and found the last one to be very exciting. It also got me out into exotic places, like the Venezuelan jungle, the southeastern Alaska panhandle, the Empty Quarter of Saudi Arabia, etc. Geoscience gives me amazing opportunities to visit these places and many more. But even more interesting to me is to be a detective – to be the first to discover something beneath the ground or the seafloor. I was the first to say where the groundwater was beneath the San Pedro Basin in Arizona and Sonora, Mexico, and the first to map where titanium sands lay beneath the seafloor off the coast of South Africa. That’s ever so cool.
* It has been shown that if you inject fluids into certain formations (e.g., deep sediments northeast of Denver, CO), you can trigger swarms of micro-earthquakes. Basically this is the ground shuddering to equilibrate and adjust itself to a slightly new stress regime. However these sorts of events are so small that they are almost never felt.They really are not earthquakes as the general public understands earthquakes.
# A forecast: in other words, there is an X% chance that there will be a magnitude Y event on the Z fault zone in northern California within the next 30 years. This is very, very different from saying that there will be a Magnitude Y event at Z location on X day - that would be a prediction. We can't do that.