Vahid Fathi
@i_sundog
12h
oh no…last thing we need now is awakened New Madrid fault…Paleoseismic evidence collected in recent decades indicates strong "earthquake triplets" similar in magnitude to 1811-12 temblors have occurred ~ every 500 years along the New Madrid fault and are likely to happen again.
View: https://twitter.com/i_sundog/status/1461188865910136834?s=20
central Mississippi Valley is most earthquake-prone region of US east of Rocky Mrs. Most quakes in the area are relatively small & occur w/in 100-mile-long New Madrid seismic zone that extends along Mississippi fr Missouri to Arkansas…
during winter of 1811 to 1812, New Madrid, Mo area was jolted by a series of three powerful earthquakes now estimated to have been of magnitude 7.5 to 8.3. quakes caused church bells to ring thousand miles away in Boston & changed the course of the Mississippi River…
in geology 101 one may be thought EQs coming i n triplets, as was the case during 1811-1812 is an oddity? perhaps, perhaps not in case of New Madrid active zone. different fault than those marking boundaries btwn two tectonic plates. as they grained past one another you get EQs…
geologists aren’t sure when next New Madrid EQ going to ring up bells in Boston.~5% of EQs take place w/in a plate, like New Madrid & r called intraplate as opposed to majority of EQs occurring near plate boundaries called interplate,like San Andreas Fault, aka transform fault… intraplate EQs are caused by stresses w/in a plate. since plates move over a spherical surface, zones of weakness are created. intraplate EQs happen along these zones of weakness. hardly mappable since they are below overlying sediments, New Madrid fault zone historical EQs