California is not doing anything unusual, so I'll talk about a series of quakes over the last week or more just south and southwest of Crete Greece. About a week ago they were in the mid M3 range, then a 4, now a 4.7 and a 4.8 in the last couple of days. This is just inside (N of) the trench for the subduction zone there. The ocean crust of the Mediterranean Sea-part of the African plate, is sinking beneath the Anatolian and Eurasion Plate/plates, like is happening beneath northernmost California, Oregon and Washington, and most of the northern and western Pacific ocean. The subduction angle in the area is about 30 deg. north (Papazachos et al., Tectonophysics 319 (200) p. 275-300). While this is not particularly steep, the slab is sinking straight down as well as sliding forwards (north). This is called "slab rollback". The upper crust has to go running off to the south to keep up with the retreating slab, causing stretching of the Anatolian/Aegean/Greek crust. So, most of the earthquakes at shallow levels north of the subduction are the result of stretching (normal faulting), along with zones of right-lateral strike-slip faulting. The North Anatolian fault area in Marmara Sea near Istanbul had generally been considered to be actively stretching. But, I inserted myself in this debate because on sub-seafloor acoustic data (seismic reflection), the folds look just like the contractional folds offshore southern California. The GPS data before the 1999 quakes do not show any N-S stretching across eastern Marmara Sea. So, I've put out a couple of abstracts saying it is squeezing, not stretching. I don't have much support from seismicity, though.

Speaking of seismicity-in the year 365, on July 21, there was a M8.3 earthquake on the subduction zone SW of Crete. There was a M8.0 in Dec 1303 on the subduction zone over by SW Turkey. These are the only M8 quakes listed for this region in a table by Papazachos et al., 1999, Tectonophysics v 308, p. 205-221. We met these guys in Greece a couple years ago, and I recall that the effects of the 8.3 earthquake were not pretty. Actually, I should reword this in case you think I am 1700 years old: I recall that they said the evidence points to some bad things happening.

For those of you with too much time on your hands, it would be really nice to have a near-real time map of western Turkey-Aegean-Greece seismicity, like the one we use for California. Maybe there is one already....
Speaking of too much time on my hands, my NEHRP annual report on Santa Monica Bay is due Dec. 1. Is that coming up soon? Chris