70,000 years ago, Mount Toba erupted, ejecting 2,900 cubic kilometers, while in 1815 Mount Tambora threw out 80 cubic km of ash, the largest in historical times, killing more than 71,000, and in 1883 Krakatoa erupted, resulting in an energy release calculated to be 200 megatons of TNT (four times times stronger than the Tsar Hydrogen Bomba, the most powerful bomb ever detonated), causing 36,600 fatalities. Super Volcano Toba almost wiped out Homo sapiens, Tambora resulted in a summerless Planet Earth and Krakatoa's eruption is said to have created the noisiest sound ever heard. All three are located in Indonesia.
Krakatau (the recent spelling of Krakatoa) largely disappeared, but Anak Krakatoa was the result. However, this relatively small volcano this past week erupted, and partially fell into the ocean, creating a 10-foot tsunami that on December 22 killed almost 500 in Indonesia.
One reason why there was no advanced alert was that there was no earthquake. Generally, that type of earth movement is what triggers the alarm.
The 26 December 2004 tsunami which killed 228,000 people was caused by a 9.2 magnitude earthquake in the ocean off the west coast of northern Sumatra, Indonesia. On September 28 of this year a 7.5 earthquake struck Indonesia's Central Sulawesi province causing an earthquake that killed more than 2,000.
On 5August2018 a 7 earthquake struck the island of Lombok, Indonesia. There was a foreshock of 6.4 on July 29 and an aftershock of 6.9 on August 19. The tsunami was perhaps only about a foot high, but the earthquake resulted in 563 deaths.
The problems with Indonesia are:
- They were created by the Ring of Fire.
- There are 18,000 or so islands.
- They have the third longest coastline, 33,939 miles. #1 is Canada and #2 is Norway, but they are not bothered much by earthquakes and volcanic eruptions.
Thus, what is currently occurring in Indonesia is confusing, for tsunamis can occur without earthquakes. NASA has developed an ionospheric measurement technique to detect and track any tsunami, but the concept is developmental. Delft University of Technology also has proposed a Global Navigation Satellite System. Much of this work was initiated by my golf buddy, Paul Yuen, way back in 1974.
The Anak Krakatoa landslide was only a 158-acre section. The Six Hours to Seattle novel I was planning to write was outlined in SIMPLE SOLUTIONS for Planet Earth. Here, I've paraphrased from my 18September2008 posting from this book:- Suppose the combination of a slow moving Category 5 hurricane stalls just south of the Big Island, bringing torrential rains to the east side, say, 48 inches over two days.
- An earthquake of magnitude 9.0 triggers the eruption of Mauna Loa and Kilauea. This is a stretch, because the largest previously, the Great Kau Earthquake, only was an 8.0. But, say it happens, and, lava begins seeping into those crevices and faults along the line of the previously defined landslide boundaries, weakened by the horrific quake.
- The extra percolating rain fluid, which also percolates to depth, becomes steam, and, with more heat, continues to expand like superheated gas. The eruptions continue for several days, heating the interstitial fluids, increasing the edifice pore pressure and, through thermal alteration, expanding fault cracks, weakening critical material interfaces and lubricating slip planes.
- Decoupling along low friction and strength layers occurs at those flow boundaries of Mauna Kea, Mauna Loa and Kilauea. Of course, those 48 inches of rain added an enormous extra weight to the already metastable underground condition.
- The collective strains induced by all the above cause a catastrophic failure of the vertical and horizontal extension of dyke intrusions, and the whole monolithic block falls at 250 Km/hour (155 miles/hour) piling up 100 kilometers (62 miles) from the coastline at a depth of 3048 meters (10,000 feet), creating a 100 meter (328 feet—about as tall as the highest building in Honolulu, but only half as high as the Seattle Space Needle) tsunami headed toward Seattle.
To gain more information for the above, this summer I flew to Seattle (and Anchorage, as I thought this Alaskan city also had potential for being a mega-tsunami victim). I spent ten days developing Six Hours to Seattle (posts in reverse chronological order):
- FIVE HOURS TO LOS ANGELES?
- ALASKA: Earthquakes, Auroras and Cabbages
- THE BEST OF ANCHORAGE
- NOT DOING MUCH IN ANCHORAGE
- SIX HOURS TO ANCHORAGE: The Longest Night?
- SIX HOURS TO SEATTLE: Space Needle and Chihuly Gl...
- SIX HOURS TO SEATTLE: Victoria
- SIX HOURS TO SEATTLE: Seattle is Hot
- SIX HOURS TO SEATTLE: Life on the Waterfront
- SIX HOURS TO SEATTLE: Hilo and Seattle Okay
- SIX HOURS TO SEATTLE: The Journey Begins
- SIX HOURS TO SEATTLE: The Speculative Science
- SIX HOURS TO SEATTLE: Mega Tsunamis
- SIX HOURS TO SEATTLE: Hint of What is to Come
Turns out I eliminated both Seattle and Anchorage as possible mega-tsunami impact sites. However, the possibility of large chunks of islands falling into the ocean causing mega-tsunamis continue to have validity, for this has happened in the past. La Palma of the Canaries has been mentioned, and the Nuuanu Landslide, largest of seventeen such debris avalanche, occurring more than a million years ago, no doubt caused a mega-tsunami that headed off for the west coast of North America. Of particular significance me, I live on Nuuanu Avenue. Bathymetric image of this slide to the right.
There was a flank collapse of Mauna Loa 120,000 years ago that caused a 1,600-foot mega tsunami. Not a typo...1600 feet tall. Something like 120 cubic miles of material fell into the sea. In comparison, the 1980 Mount St. Helens eruption and landslide was less than ONE cubic mile. This boulder was deposited half-a-mile inland on the island of Santiago by Fogo Volcano collapsing into the Atlantic Ocean 73,000 years ago.
So Indonesia will continue to suffer from natural disaster cataclysms for a long time to come, thusly affecting much of Planet Earth also. As tranquil as Hawaii might be, our volcanoes are still active, and the age of our islands are such that the probability is increasing for mega-tsunamis throughout the Pacific. However, we only have a few islands and a volcano or two. Indonesia has 18,000 islands and 127 active volcanoes. I bet you simply ignored World Tsunami Awareness Day last month.
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