Saturday, May 26, 2012

Valley of Ten Thousand Smokes

No one alive remembers an eruption as massive as the Novarupta-Katmai Eruption of 1912. The Novarupta-Katmai eruption was the largest volcanic eruption of the Twentieth Century. This massive volcanic event occurred in Alaska in an area that was later named Valley of Ten Thousand Smokes
No one living today can recall a volcanic eruption of such magnitude, or of such potential disruption to human safety and systems, and yet we know that many volcanic complexes in the United States and around the globe are capable of someday erupting similar or larger volumes of molten rock and ash.
~Marcia McNutt, USGS Director
The site has been preserved since 1980 by the Katmai National Park and Preserve.

Katmai Calder - Mount Katmai, Alaska
In June of 1912, glowing hot pumice and ash spewed from the Novarupta-Katmai volcano. It flowed over terrain destroying life in its path. The ash, pumice, and gas ejected cast a haze-darkened sky over most of the Northern Hemisphere.

The Novarupta-Katmai eruption:
  • Was ten times more forceful than the 1980 eruption of Mount St. Helens
  • Buried more than 40 square miles in volcanic deposits as much as 700 feet deep. 
  • Spewed 7 cubic miles of ash as far as the Mediterranean Sea. 
  • Caused an acid rain that disintegrated clothes on clotheslines as far away as Vancouver, Canada.
  • Reduced visibility 100 miles away in Kodiak, Alaska where for two days a person could not see a lantern held at arm's length. 

The volume of ash ejected by Novarupta-Katmai, if concentrated in one place, would be enough to bury the city of Anchorage 3 miles deep.

Volcanology is the study of volcanoes, lava, magma, and related phenomena. The term volcanology comes from the Latin word vulcanus
In ancient Roman religion and myth, Vulcan is the god of beneficial and hindering fire, including the fire of volcanoes. 
At the time of the Novarupta-Katmai eruption in 1912, the study of volcanic eruptions was in its infancy. Researchers had few points of comparison. Field investigations of the Katmai site provided key insights that contributed to advances in volcanology. Novarupta-Katmai has been one of the most studied eruptions in the world.

I have seen so many eruptions in the last 20 years that I don't care if I die tomorrow.
~Maurice Krafft, Volcanologist, on the day before he was killed on Unzen Volcano, Japan 1991.


Alaska Volcano Observatory - Katmai Reported Activity.
Alaska Volcano Observatory - The Great Katmai Eruption of 1912: A Century of Research Tracks Progress in Volcano Science.
USGS - The Novarupta-Katmai Eruption of 1912—Largest Eruption of the Twentieth Century: Centennial Perspectives.
Wikipedia - Valley of Ten Thousand Smokes.
Wikipedia - Vulcan (mythology).
Wikipedia - Volcanology.

Saturday, May 19, 2012

Earthquake Magnitude

2012, Magnitude 8.6
Off the west coast
of northern Sumatra
Seismologists express earthquake size in units of magnitude. Magnitude is obtained from instruments called seismometers that measure motions of the ground.

The Moment Magnitude Scale is commonly used to measure the size of earthquakes.

Using the Moment Magnitude Scale, earthquake size is given in terms of the energy released based on the seismic moment of the earthquake. The seismic moment is equal to the rigidity of the Earth times the average amount of slip on the geologic fault and the size of the area that slipped.

The Moment Magnitude Scale was developed in the 1970s to replace the Richter Scale.

Shaking Amplitude

Magnitude is expressed on a base-10 logarithmic scale. An earthquake that measures 5.0 has a shaking amplitude 10 times larger than one that measures 4.0. Each whole number increase in magnitude represents a tenfold increase in measured shaking amplitude.

Energy Released

Each whole number increase in magnitude corresponds to an increase of 32 times the amount of energy released.
We learn geology the morning after the earthquake
~ Ralph Waldo Emerson
How Much Bigger?

The USGS How Much Bigger Calculator is an interactive tool that shows difference in the intensity and in energy released between two earthquake magnitudes.

Recent Large Earthquakes

The largest recorded earthquakes for each year over the past decade are shown in the table below:

Year Date Magnitude Human
2012 04/11 8.6 0 Off the west coast of northern Sumatra
2011 03/11 9.0 20896 Near the East Coast of Honshu, Japan
2010 02/27 8.8 507 Offshore Maule, Chile
2009 09/29 8.1 192 Samoa Islands region
2008 05/12 7.9 87587 Eastern Sichuan, China
2007 09/12 8.5 25 Southern Sumatera, Indonesia
2006 11/15 8.3 0 Kuril Islands
2005 03/28 8.6 1313 Northern Sumatra, Indonesia
2004 12/26 9.1 227898 Off West Coast of Northern Sumatra
2003 09/25 8.3 0 Hokkaido, Japan Region

Human fatalities from seismic events depend on the magnitude and depth of the event and the proximity of the epicenter to concentrations of human population. Off-shore Earthquakes, volcanic eruptions and other underwater disturbances can cause a series of waves, or tsunamis, that can be destructive to on-shore populations.

Saturday, May 12, 2012

The Great Dewdrop

If you wonder about the sensory beauty of the earth, take heart knowing that more of it is protected than ever before.

Protected areas cover about 8 million square miles of land and sea. By comparison, protected areas now account for more than twice the area of Canada (see There Are More Protected Places on Earth Now Than Ever Before).
Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts. There is something infinitely healing in the repeated refrains of nature -- the assurance that dawn comes after night, and spring after winter.
Rachel Carson
Edward Weston, Carmel, 1938

When we contemplate the whole globe as one great dewdrop, striped and dotted with continents and islands, flying through space with other stars all singing and shining together as one, the whole universe appears as an infinite storm of beauty.
John Muir
The mission of GrokEarth is to promote a fuller understanding of earth phenomena and to promote awareness of its infinite sensory beauty.
"In the end, we will conserve only what we love; we will love only what we understand; and we will understand only what we are taught."
― Baba Dioum, Senegalese conservationist

Saturday, May 5, 2012

Waves in Nature

Surface Waves
Are you an observer of waves?

I was an observer of waves in water long before I knew waves were everywhere.

I observed waves long before I knew that light waves make things visible, or that sound waves make things audible, or even that solid things vibrate at a certain frequency.

In waves we observe how energy changes from one state to another and back again.
It would be possible to describe absolutely everything scientifically, but it would make no sense. It would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure.
~ Albert Einstein
Dunes Oceano, Ansel Adams, 1963
Ansel Adams, Dunes Oceano, 1963
A wave travels through space-time and is accompanied by a transfer of energy, but there's something more poetic and indescribable about waves.

There are waves one creates and waves one experiences, waves one can see and waves one can feel.
Dunes Oceano, Edward Weston, 1936
Edward Weston, Dunes Oceano, 1936
The first wave says, "You don't understand! We're all going to crash!
All of us waves are going to be nothing! Isn't it terrible?"

The second wave says,
"No, you don't understand. You're not a wave, you're part of the ocean.

~ Morrie Schwartz,
   from Tuesdays with Morrie
When does a wave begin? When does it end? Are the terms beginning and end relevant in the context of waves?
I am you; you are me. You are the waves; I am the ocean. Know this and be free, be divine.
~ Sri Sathya Sai Baba