Tag Archives: earthquake

How’s it shaking?


Sensor monitor reading at University of Alaska

Interior Alaskans felt the Earth move a bit on Tuesday morning. It wasn’t a big earthquake, at only magnitude 4.6, but it was widely felt at 7:18am. It’s note worthy, mainly because it has been a couple of years since I felt one pass through.

On Sunday morning, Kaktovik, which is located on the Beaufort Sea coast, woke up to a 6.4 magnitude quake. It was the largest earthquake ever recorded on Alaska’s North Slope.

Earthquakes in Alaska are far from unusual. An earthquake is detected once every 15 minutes, on average, within the state. In 2014, Alaska set a record with over 40,000 shakes. Over the past five years, the Alaska Earthquake Center has reported over 150,000 earthquakes. Of those, 31 had a magnitude over 6.0. and four went over 7.0. Seventy-five percent of all earthquakes over 5.0 within the United States happen in Alaska.

The 7.9 magnitude quake, that hit us in 2002 when the Denali Fault ruptured, is the largest I have experience. The 1964 Good Friday Earthquake was a magnitude 9.2, and it is still the second largest earthquake ever recorded anywhere on the globe.

Graph and stats credit: Alaska Earthquake Center


Nepal

7.8 Magnitude Nepal Quake

As a resident of Alaska, I am well aware of the destructive power of a large earthquake. Along with many other Alaskans, I have experienced a 7.9 magnitude quake. There are still many here who remember what it was like to live through the Good Friday Earthquake of 1964. That 9.2 magnitude quake devastated South Central Alaska.

There are many organizations that are gearing up to offer assistance to the people of Nepal. If you are so inclined, find one that you are comfortable with and help send some relief.

The American Red Cross is just one such organization:
http://www.redcross.org


Chile & Everest

Two acts of Earth’s power was caught on camera recently:

A hiker in Chile was filming a waterfall in Llianquihue National Reserve, when the Calbuco volcano erupted on 22 April. The last time Calbuco erupted was in 1973. The ash plume was sent over 1000 m into the air.

Calbuco erupts
The eruption of Chile’s Calbuco. Photo credit: David Cortes Serey/AFP/Getty Images

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A German climber, Josh Kobusch, was on Mt Everest when the 7.8 magnitude Nepal earthquake struck, triggering an avalanche which roared into the Everest Basecamp on Saturday. Kobusch’s footage of the avalanche is the first to come off of the mountain. At least 18 people died on Everest from the avalanche and over 3300 people have died due to the earthquake overall.

The 7.8 quake was the worst to hit Nepal since the 8.0 that struck in 1934, which all but wiped out the cities of Kathmandu, Bhaktapur and Patan.

Nepal Earthquake
Destruction from the 7.8 earthquake in Bhaktapur, Nepal. Photo credit:REUTERS/Navesh Chitrakar


Scotch Cap Lighthouse

Scotch Cap Lighthouse 1903
The Scotch Cap Light in 1903.

The Scotch Cap Light was the first lighthouse on the outer coast of Alaska. It was built on Unimak Island in the Aleutian Chain in 1903.

Scotch Cap Lighthouse
Scotch Cap Light in 1940

In 1940, a new Scotch Cap Light was built out of reenforced concrete and a fog signal was added. From the beginning, the lighthouse was the scene of several shipwrecks, including the Columbia in 1909, which forced the crew of 194 to spend two weeks on Unimak as guests of the lighthouse keepers until they could be rescued. And in 1930, a Japanese freighter became lost in a snowstorm and beached in front of the light.

The 1946 Aleutian Islands Earthquake hit the chain of islands on April 1 of 1946. The 8.1 magnitude quake generated a Pacific wide tsunami. The massive wave wiped Scotch Cap Light right off the face of Unimak Island. Anthony Petit, the lighthouse keeper, and his five man crew were killed by the wave that is estimated to have been at 130 feet high.

Unimak Island 1946
Unimak Island after the 1946 tsunami.

The tsunami that resulted from the Aleutian Earthquake killed 165 people: 159 in Hawaii and six in Alaska. It took the tsunami 4.5 hours after the quake to hit Kauai and 4.9 to strike Hilo, causing over $26 million in damage. After the destructive tsunami, the Seismic Sea Wave Warning System was established in 1949, eventually becoming the Pacific Tsunami Warning Center.

Hilo 1946 Tsunami
Residents of Hilo, Hawaii fleeing the 1946 tsunami.

Photos of Unimak and Scotch Cap courtesy of USCG. Hawaii photo courtesy of NOAA


Whole Lotta’ Shakin’

Jerry Lee Lewis in 1957

Alaska rattled its way into another record during 2014. The Alaska Earthquake Information Center recorded 40,686 earthquakes in Alaska in 2014. The previous high of 32,000 was attained in 2003; 2013 saw 28,000 shakers within Alaska.

Some notable quakes among the 40K:

• The Noatak-area “swarm,” a series that saw five earthquakes greater than magnitude 5 strike the northwest Brooks Range from April to June.
• A magnitude 7.9 quake in the Rat Islands on June 23, the largest in Alaska since 2002.
• A magnitude 6 earthquake under Seward Glacier in the Saint Elias mountains on July 17.
• Another magnitude 6 quake, this time in Palma Bay in Southeast, on July 25.
• The 5.2 magnitude earthquake near Minto on Aug. 30 that gave Fairbanks a jolt.
• A 6.3 magnitude quake near Skwentna on Sept. 25 that caused several buildings in downtown Anchorage, 80 miles away, to be evacuated as a precaution.

All information and statistics come courtesy of the AEIC.
Their site: http://www.aeic.alaska.edu


Be Wary of Minto

We had another cabin shaker this morning sent from the Minto area. Just a 5.1, but these quakes are becoming a bit of a habit.

Deep beneath the muskeg of Minto Flats lies two long faults, that give Fairbanks the majority of the earthquakes we feel. Interestingly, the past three shakers, all at around the 5.0 magnitude level, have come from a previously unmapped fault. The Minto area fault lines come from the pressure placed on the Alaska mainland by the Pacific Plate.

This week, people have been talking about the 6.0 magnitude 1995 earthquake that originated under Minto Flats. Everyone that has mentioned it, said that the shaking was far more violent than the 7.9 Denali Quake, which happened in 2002. I imagine that is because Minto is roughly half the distance to Fairbanks as the epicenter of the Denali Quake.

Without a doubt, the best duck hunting I have ever experienced was out in the boggy quagmire of Minto Flats. Amazing to think of fault lines lying under that vast morass, and fault lines that could easily spring a 7.0 or larger earthquake.


Minto sends out another shaker

Interior Alaska had another 5.0 earthquake on Monday. Due to my incredibly full summer, I’m just now getting around to my own needs, so I was hauling and stacking firewood when the tremor passed underneath. I’m proud to say I actually felt this one.

When the shaking stopped, I wheeled over another load of wood to the woodshed, and found that the first row of stacked firewood now had a pronounced bow in the middle of the row. Since I live outside of any city limits, my wood pile is not subject to inspections by the city seismic engineers. I can build any type of woodshed I want, and stack it any way I please, without any governmental interference.

Now some people would claim that the bow in the stacked row of wood after a 5.0 earthquake just goes to show how we need seismic engineers inspecting our woodpiles before some sort of firewood tragedy happens. Of course, those people live in Anchorage, or locales further south.

It may be true that my stack of firewood would not pass the seismic engineers inspection. Each log is not tied to the other with structural ties; they just kind of lie there on top of each other, in a now, somewhat wavy wall of birch & spruce. The way I look at it, the wall may have a bit of a wave to it, but it survived a 5.0 shaker. How many wood burners in Minnesota or Iowa can say that?

So I made an attempt to push the wave back, then put up two more rows of stacked wood to cover, and theoretically support, the wavy row. I go into this new, wood burning season, with full knowledge and understanding, that if we get another 7.9 like the 2002 Denali Quake, I’ll be picking up and re-stacking some firewood.

Living on the edge.