a reply to:
rbkruspe
I've also got that nagging feeling. And I have to admit it's becoming quite bothersome.
Besides the usual suspects for locations of larger quakes, I've got my eye on the fault off the coast from Portugal (that hasn't been hugely active
since 1755) and also the fault that continues on from that and runs east into the Mediterranean and down past Sicily and has a related one that
affects the Straits of Messina.
If you look at the USGS world quake map, some sections of the main fault are not drawn in because they are not sure exactly where it is. Why? Lack of
data from prior events. But seeing as there's general agreement that the African plate is colliding with the European plate, then the fault is there
somewhere. If you draw your own imaginary lines to fill the gaps you probably won't be far out.
Back in 2004, National Geographic reported in an article
HERE that the 1755 "Lisbon Earthquake", which has been
estimated as a mag 8.7 Mw, was probably a subduction event. They go on to say the evidence indicates the region there is "locked" and will likely
let go again one day when the strain becomes too much.
However, they do say that the intervals between great quakes in that region may have intervals of 1,000 to 2,000 years.
All the same, I'm concerned about the region so thought it best to mention it. Using the CSZ as an example as its prior tsunamigenic quakes have been
studied in some detail by Chris Goldfinger et al over the past couple of decades, the intervals between previous great quakes there off the US PNW
have varied considerably, from a low of maybe one or two centuries to 1,000 years plus.
So, while an average interval is useful to know, it doesn't mean that the actual intervals will always be close to the average.
I am not saying that I believe a major quake off Portugal or within the Med basin (eg Sicily / Messina Straits) is imminent. I am only mentioning that
it's become one of my main regions of focus in the past few days, but I cannot offer any physical evidence as to why. Statistically, the odds are
very good that nothing major will happen in either of those two (somewhat connected) regions in the coming days or even weeks. I'm just voicing my
concerns and that is all.