00:01In this case, it was triggered by a landslide, which was a huge and giant landslide generating
00:09that megatsunami wave.
00:10So this is the aftermath of a huge block collapsing into the water and surging the water to a
00:21very high altitude and elevation.
00:24In Tracy Armfjord in southeast Alaska, the tsunami, the megatsunami waves, it was triggered
00:30by this giant block collapsing into the water.
00:34And the landslide itself, it was attributed to a glacial retreat.
00:40The glacier at the base of this slope acts as a kind of buttress of physical support.
00:47And we know that the glacier has been retreating for decades.
00:51And once the glacier shrinks and pulls back, it leaves the slope bare and unsupported and
01:03allows it to destabilize and also eventually to collapse.
01:08And that's the chain of steps that has been the case here.
01:11A landslide tsunami in Tracy Armfjord was not on the radar, so it was not a known concern.
01:17It is now, but it was not on anyone's risk or hazard map.
01:22So there was no clue, no kind of cautionary movement, a rockfall, cracks or whatever that can be alarming
01:31for us.
01:32So that made the event to be not anticipated.
01:36And we also tried in our study to do a retrospective assessment just to see whether we can see any
01:47kind of movement or signals that can act as a precursory signal prior to the collapse.
01:55The satellite data didn't show any considerable movement.
01:59But what we found was some small earthquakes and tremors preceding the collapse, which is really promising.
02:07And it's one of the most popular destinations in Alaska.
02:11And during the summer, it is visited by three cruise ships and several more vessels daily.
02:20And this was a near miss event just only because of the timing.
02:25It happened early morning about 530 a.m.
02:28And nobody heard about this enormous event just because it was a kind of fortunate timing.
02:38And you see these cruise ships, they are carrying some of them.
02:44They carry, I think, up to 6,000 passengers.
02:47They are literally floating cities in the area.
02:50And imagine hitting by a wave of that scale.
02:54That's not survivable.
02:55And it could easily turn into a horrifying disaster, I would say.
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