Earthquakes, earthquakes

Yesterday I mentioned that an astronomer attempting to observe today's Uranus ring plane crossing from the Keck telescopes in Hawaii was fighting both hurricanes and earthquakes; I heard on the news last night that the seismic activity continues south of Hilo, and indeed you can see if you check the USGS Earthquake Hazards Program page for Hawaii that there have been two more earthquakes of decreasing size since the magnitude 5.4 one last week. I'd forgotten about it until just now when I felt another earthquake here at my house, which I guess must be an aftershock to the quake I felt last week. None of these was big as earthquakes go; just a reminder that the solid rock under our feet is not so solid as to be immobile, but solid enough to transmit the energy from earthquakes or other ground-shaking events long distances.

I love these individual quake event pages that the USGS produces; they are a fantastic way to collect scientifically valuable data from the general public, and allow the public to participate in research that should, eventually, produce positive results for them. As one example, here in California, before anyone can build, they must check out the Alquist-Priolo Fault Zone maps to see where geologists have identified potentially hazardous faults. Buildings used for human occupancy (as opposed to other types of buildings like garages) cannot be constructed anywhere within these fault zones. Which is not to say that if you build outside the fault zone you're safe from earthquakes; but at least the ground shouldn't rupture through your building. The more data we collect on where earthquakes occur, the better we can protect against their negative effects. It's quite parallel to all those amateur astronomers out there who patiently track the orbits of potentially hazardous asteroids, helping researchers to determine whether they do, in fact, pose any threat.