On the necessary evil of earthquakes

[BaalChatzaf]

The recent earthquake that has wrecked the city of Christchurch in New Zealand got me to thinking. It turns out that our life is possible only through the same processes that produces earthquakes. The magnetic field of this planet is generated by the convection of a a molten and hot inner core. Without that motion we would have no magnetic field surrounding the planet to protect us from the fury of the sun. So if we had a nice sold planet we would soon be cooked alive by our sun. And if not cooked, left without the seas and the atmosphere that would be blasted away by the emission of energetic charged particles from the sun. We would become Mars in relatively short order.

The price of staying alive on this planet is putting up with earthquakes. The rational response is to build our houses and to roll with the trembles and the shimmying. That would mean no skyscrapers in very seismic regions. Our best building practices protect all buildings up to magnitude seven quakes at the most. A 9.3 quake such as hit Juneau Alaska back in the 50's would take down any tall building (20 stories or more).

Ba'al Chatzaf

[sjw]

Yes, this and many other issues were covered in this book by Bill Bryson: http://www.amazon.com/Short-History-Nearly-Everything/dp/0767908171

In spite of some technical inaccuracy, I highly recommend it.

Shayne

[william.scherk]

A 9.3 quake such as hit Juneau Alaska back in the 50's would take down any tall building (20 stories or more).

Wikipedia has a list of the most powerful earthquakes. I think you may mean to refer to the 1964 Alaskan Earthquake/Tsunami. This was the second-largest recorded quake at 9.2, and was centred near Anchorage (900km from Juneau).

Your main point about relations between Earth's magnetosphere, high-energy photons/solar wind, core, crust, human life, and tectonic restlessness built into our globe -- quite compelling.

[BaalChatzaf]

A 9.3 quake such as hit Juneau Alaska back in the 50's would take down any tall building (20 stories or more).

Wikipedia has a list of the most powerful earthquakes. I think you may mean to refer to the 1964 Alaskan Earthquake/Tsunami. This was the second-largest recorded quake at 9.2, and was centred near Anchorage (900km from Juneau).

Your main point about relations between Earth's magnetosphere, high-energy photons/solar wind, core, crust, human life, and tectonic restlessness built into our globe -- quite compelling.

Anchorage! Of course. That was a wall banger it was. Not a sky scraper in the continental U.S. could have withstood that one. Thank you for the correction.

Ba'al Chatzaf