Yes <The bronze and most of the iron age (unit 900 to 1200 years ago) civilizations where paying a lot of attention to Equinox and Solstice
Any comments?>
When people live basically outdoors, the climate matters a LOT. People now spend fortunes on housing because it's worth the effort to be snugly warm inside, or cool in the shade, perhaps even with air-conditioning.
When spring starts, it's a great time, when autumn arrives, it's going to get cold.
But regarding earthquakes, for a few decades I have been a volcano predictor [and the same thing applies to earthquakes of course].
The sun and moon distort Earth as orbital positions change as shown by tides surging continuously around the oceans. The same tides of magma under the crust are surging but of course not so high or we'd be shaking flat out. They are vastly more viscous than water so the surge is small.
But there is still a surge. There is another effect of the orbits which is to lower pressure. When gas is compressed, it liquefies at a particular pressure at a given temperature. If the pressure is reduced ever so slightly, it turns to gas at much greater volume.
That's how volcanoes go. When the magma chamber is loaded with enough magma and liquefied organics and water, the tidal surge arrives, the pressure in the column of liquids is reduced, a little bit of liquid turns to gas, pushing up, the lake surface is displaced sideways, lowering the pressure more, allowing more liquid to turn to gas, and that pushes the surface away, lowing the pressure more, and in a short time, the reduced pressure results in a steam eruption at the surface followed by the whole column of liquefied gases turning to gas, roaring up with megatons of frothing pumice, with the organic molecules igniting in air, causing a vast explosive launch to the sky.
It's not so much the equinox as the tidal timing. A king tide is the time to be especially wary. With sun and moon aligned and orbits close, and with angle of orbit just right, with the magma chamber loaded, with more coming in from the subduction zone, the system is ready to pop. A butterfly taking off might be the straw that breaks the camel's back [to mix a metaphor].
It is a good idea to not live inside active volcanoes as they do at Taupo and Rotorua. Contrary to popular thinking, there isn't much warning at all [I guess minutes] that an eruption is going to happen.
With liquid to gas eruptions, they don't do the pretty squirty red lava fountains as in Hawaii and Auckland, which are fun to stand around nearby and watch, they do a fantastically enormous blast to the sky in a short time.
It's amusing that the NZ government has "for your own good" security around Christchurch, which has already fallen down so it won't be falling down again, but they allow people to wander around in Wellington, spend all day every day inside buildings which will go splat on the ground as soon as an earthquake hits, which it will. Also that the government doesn't at least warn people in Taupo that they are going to die if they are there when the volcano goes up, which it will, with a probability of about 1:10 in any 70 year period. That's a 1 in ten chance of seeing the volcano go if somebody lives their whole life there. I don't like those odds for myself. Something like 300 km is a good distance for viewing, not in a house at the edge of the lake.
The cause of eruptions and earthquakes is plate tectonics and subduction of organic sediments as the fuel for eruptions, but the trigger is orbital mechanics. Beware the ides of March and spring tides, with low air pressure and low lake levels and low groundwater levels.
Mqurice |
