Question Earthquakes

Arcanist Lupus wrote: I'm a California boy. My rough rule of thumb for earthquakes is 1-2: you didn't feel it. 3-4: you might have felt it. 5-6: something might break (this includes people, especially in the high 6s), 7-8: I hope you're okay, 9: How unlucky were you?

I think that the best modern example of the importance of infrastructure in dealing with earthquakes is the 2010 Haitian earthquake. It was only a 7.0, yet the death toll was 10 times that of the 9.0 that destroyed Fukushima.

Of course, there are a ridiculous number of factors that affect earthquake destruction beyond it's magnitude and the quality of infrastructure (depth and type of seismic event are the two main ones that come to mind)

As far as earthquake preparation goes, my family's rule #1 for proofing a house is to make sure that there is nothing* that is capable of falling onto any of the beds. Then, if you wake up to a major earthquake, you (and your children!) are already in one of the safest places of the house.

*stuffed animals and decorative pillows are okay.

I don't feel like cluttering up a thread set up to legitimately check up on a valued member of the community with my opinions on earthquakes so I'm starting a new thread.

Good scale. I agree with it as my previous comments on what I would be worrying about should show.

Now for something ridiculous, the "big one" that they are predicting for the island is supposed to be in the range of 9 to 12. Yeah some believe it will be a 12.Llook at the scale above and tell me I'm wrong in calling a bit of hogwash on those outliers. Alternatively some believe that the 6.9... I think, that we had back in the early 2000s was the "big one" and we have nothing to worry about.

My thoughts were that it's a bit like bush fires down here in Oz.

This is the joy of living in the Midwest and dealing with our local earthquakes. 2008 Illinois Earthquake

This is about 130 mi (210 km) from my home. It shook my house enough that I tried to figure out what it was. My first thought was a train, but there was no train noise, and it was worse than any train I have felt. My second thought was the wind, but there was no wind sound, and it was more violent than the occasional 60+ mph wind gusts that hit my home. My third thought was a giant monster grabbed my home and shook it, but there was no crunching sound of a monster. (Seriously that was my third idea.)

Still waiting for the big one from the New Madrid fault.

One thing that has always puzzled me about the reporting of earthquakes is exactly how the strength of an earthquake is determined.

I know that the strength is reported based on the Richter Scale (which I believe is logarithmic rather than incremental) but the initial strength value reported always seems to change over later reports. How much of this change is due to media sensationalism and how much is due to the refining of incoming data I don't know.

I thought that seismometers were calibrated to a common set of values so, in theory anyway, they should all record an event in the same way. That might be a very simplistic viewpoint I'll admit. I assume that the variation in the media reports of the strength of an earthquake is due the refining of new data but I've always wondered HOW that works?

Britain has so few earthquakes that are big enough to be felt, let alone make it into the media, that this has always been an area of intellectual curiosity to me whereas it might be of much more direct interest to folks in other parts of the globe.

John.

The Richter scale is logarithmic and based on the frequency of the earthquake. I believe going up 1 is equivalent to 10 times the severity although it might be 100 with 10 being going up 0.1, it has been a while since I learned this stuff.

Also I believe the type of earthquake factors in, and it's location.

A 6.3 might be observed at such and such a time, but when looked at more closely the number might change. What was 6.3 at location X, instead near the epicenter is more like 6.8.

As for type of earthquake you have deep ones, and shallow ones. Both of which are reported the same way, but measured differently. The Richter Scale is just what the geologist use to lay person to describe the scale of the quake.

Fun fact above Richter Scale 7.0, the Richter Scale is meaningless, also if the quake is large enough it can't be measured by the Richter Scale. From 8.0+ the quake's frequency is too great to be measured, which is why it was abandoned in 1970s, but it's still in use because it's sexy.

My personal scale goes like, 'huh I didn't notice' to 'what was that' passing 'crap things are falling' to 'HOLY...'

I missed my calling when I didn't try out for Jeopardy...