It could depend on how you want to define it. Many places get earthquake swarms, Yellowstone had 800 in two weeks a couple of years ago, but the strongest was less than a 4. Iceland recently had 800 quakes in 24 hours, but again the worst were a couple of 4s.
Aftershocks are actually described by equations which can predict their frequency. I’m just guessing but Japan’s probably follow the equations and larger earthquakes would probably have more aftershocks.
The data is out there, but I couldn’t really find anything that came close to answering your question. I think it’s because earthquakes are thought of as events which happen from the first quake until the aftershocks go back to normal background levels, and most large ones seem to last a couple of weeks. No one seems to put it into 24 hour terms.
i was thinking per given region (that sector of map, for example) and all above 4.5 (as the USGS plots them).
it might just be from a lack of paying attention, but i can’t recall ever knowing there were that many >=5.0 quakes concentraed in such a small area.
and i think some of these are being considered isolated “new quakes”–like the one on the west side of the mainland that was a 6.1.
i guess everyone is fascinated and heartbroken, as the board is lit up with related questions.
what a surreal ordeal.
so, on the matter of statistics:
are we above average for substantial disasters lately? i just read an article about how this will change the insurance market, coupled with new zealand, floods in australia, china’s quake, floods on the east coast and all manner of catastrophe.
the doomsayers are already pointing at the sky—but are we really in a more dynamic time or are we just living on a communicationally smaller planet, learning of disasters faster and more efficiently pin-pointing causes?
i tend to think we just live in a world where we just “hear about it more” rather than “it’s happening more.”
but then again, we set snow fall records as well as a new record low temp for our state this year…
last summer we had record flooding here–my home was not spared…it’s been (seemingly) dynamically rough times when it comes to nature…
No, the rate of large earthquakes has not changed since we’ve begun recording them. “Disasters” are more prevalent though because there are more people around to be killed by them. Were the 1812 New Madrid earthquakes disasters? Rerouted the Mississippi, 8.2ish IIRC. Today they’d cause tens or hundreds of billions in damage and thousands of deaths, but nothing happened back then, all down to the population increase.
So “is it happening more?” Can be yes or no, depending on if you’re asking if there are more earthquakes or if there are more earthquakes that kill people.
Yeah, hundreds if not thousands of earthquakes happen across the world every day. It’s just that the vast majority of them are very small and may not even be noticeable to human perception except via instruments (or unless you’re standing right on top of the epicenter). The depth from the surface varies greatly too, so there are earthquakes happening way underground that we don’t even feel.
Also, since most of the planet’s surface is empty (as well as the oceans), many earthquakes occur in areas where there is little or sparse human population, and just not much to damage.