Ice core records from the Arctic show that Alaska’s Okmok Volcano had a massive eruption in 43 BCE. Following the eruption, there was an abrupt cooling globally, which led to crop failures, famine, disease, and eventually, social unrest. The Mediterranean region was no exception to this.
Such a shift in climate, coming a year after the assassination of Caesar, would have put great pressure on local powers. Strain was also felt in Egypt.
Okmok has a very active history. At one time, it had a 150 meter deep lake in its crater. A notch in the rim eventually drained the lake, although some small remnant lakes remain near cones B & D.
The eruptions of Okmok 8300 and 2050 years ago earn a Volcanic Explosivity Index rating of 6, which puts it on par with Novarupta and Krakatoa.
On 12 July 2008, Okmok erupted without warning, sending ash 50,000 feet into the air. It erupted continuously for almost six full days, causing transportation problems in the air and on the water for the region. That eruption was ranked a 4 VEI, which is considered “cataclysmic”.
Back to 43 BCE. The decade following the eruption was one of the coldest in a millennia, with 43 and 42 BCE being some of the coldest years. It is believed that a temperature drop of 7C from normal was a result of the volcanic eruption on the other side of the globe.
An undersea volcano erupted Saturday near the island of Tonga. The satellite imagery above is pretty intense, and the ash plume reached 20km above the earth.
Tsunami alerts were put out almost immediately, and the island of Tongatapu had waves flooding into the capital.
The tsunami reached Alaska’s southern coast this morning, with King Cove recording the highest waves at 3.3 feet.
That wasn’t the only wave to hit Alaska from the eruption. The shock wave of the event caused a drastic air pressure change over the state as well.
Can you hear a volcano erupt from almost 6000 miles away? It turns out that you can. Many people, who were up between 3:30-4:00 am on Saturday reported hearing a sonic boom. It’s telling that many Alaskans initially reported being awaken by a large boom, and most of them assumed it was a “moose on the porch”. Various infrasound recorders placed around the state by Alaska Volcano Observatory confirmed that the sound heard was the volcanic pressure wave, not a moose.
I find that absolutely fascinating.
A second eruption pressure wave traveled over Anchorage 19.3 hours after the first wave, traveling in the opposite direction.
As of this writing, details of the damage remained sketchy at best. It is known that waves entered Tonga’s capital, and that a thick layer of volcanic ash was dumped on the island. No deaths have been reported at this time, and it is not known how many islands have seen damage from tsunamis or ash fall. Tonga’s internet service, much like Alaska, is served via undersea cables. It is thought that those cables were damaged in the eruption.
New Zealand has sent military aircraft to Tonga to assess the damage.
The largest icebreaker of the three in the service of the United States Coast Guard, will sail through the Northwest Passage at the end of this summer. The sailing will be a joint venture with the Canadian Coast Guard.
The Cutter Healy is named after Captain “Hell-Roaring” Mike Healy, who was captain of the U.S. Revenue Cutter Bear. The Bear sailed the Alaskan coast for decades. The icebreaker Healy has accommodations for the entire crew, as well as for up to 50 scientists. The Healy can continuously break through ice up to 4-1/2 feet thick at 3 knots, and up to 10 feet thick, when “backing & ramming”. The Healy is designed to operate at temperatures down to -50F, and was the first U.S. surface vessel to reach the North Pole unaccompanied.
The upcoming mission through the Northwest Passage is officially a joint research and educational collaboration. That may very well be true, but it’s hard to ignore the geopolitical message that will be sent along with the research.
As the sea ice in the Arctic diminishes, clearly transport through the Northwest Passage will increase.
Currently, plans have the Cutter Healy leaving Dutch Harbor in mid-August for the Northwest Passage. By mid-September the icebreaker expects to do exercises out of Nuuk, Greenland around Baffin Bay.
I thought I’d post a site here that someone recently shared with me. It’s sort of a modern day Etch-A-Sketch for icebergs. There is a blank ocean where you etch-a-sketch in an iceberg to see how your shape would float.
Things to keep in mind: The sketch and canvas are only two-dimensional, an actual iceberg would be 3-D. An iceberg floats with 10% of its mass above water.