Shell Mound wrote:Kingarabian wrote:cycloneye wrote:Even in Puerto Rico and other Caribbean Islands and in Texas GOM coast there is data from NOAA of minitsunami.
How does this compare to, say, Pinatubo? So far this eruption appears to have been weaker than that of 1991, to not mention that of Krakatoa (1884).
I'm no volcano expert by any means, but I did have a brief volcano obsession when I was younger so I can elaborate a little bit. Volcano intensity is measured by means of VEI (volcanic explosivity index), which is a logarithmic scale based on the ejecta volume (even though other factors such as plume height, injection into the upper atmosphere and qualitative observations are also taken into account). Official analyses are still ongoing so (similar to f.e. after a tornado outbreak) it'll still take a while before we know what exactly the strength of the eruption was. Most volcano (semi-)expert posts that I've read so far are in agreement that the major eruption was VEI 4 - 6. People saying VEI 6 are in the minority though, most people seem to agree on VEI 5 (and some suggest VEI 4 since they propose that the underwater effect may have made the explosion look bigger than it really was). VEI 5 would be roughly one order of magnitude weaker than Pinatubo or Krakatoa, the latter two both being VEI 6 eruptions. If Hunga Tonga's eruption was VEI 5, it would be only the second VEI 5 eruption of the 21st century (the only other one was in 2011) and, depending on more detailed analysis, thus possibly the strongest eruption of the 21st century so far. But I'm getting ahead of myself, there's still a lot of uncertainty. And while we don't know for sure (I mean, the eruption isn't even finished yet for all we know), most people agree that the eruption was indeed weaker than the likes of Pinatubo or Krakatoa. Whatever it may be, it was still catastrophic so I'm absolutely not trying to diminish the impact of this eruption. I still haven't seen a lot of footage and/or messages from Tonga, I hope the people there managed to get to safety from the tsunami in time.