The Greatest Recorded Earthquake

PROLOGUE

I was born in Santiago, but my earliest memories date from the years my family spent in Iquique, in the far north of Chile. There, I first attended school. There, I made my first friend, Carlitos. There was created my most vivid early memory….

Our house faced a convent.  Normally, high convent walls concealed nuns of a cloistered order. But in Chile earthquakes are a part of life. And what one does in an earthquake of any magnitude is rush out into the middle of the street…. And so my family did early one morning when our house began to rattle and shake, along with everyone else who lived on that street, including the nuns.  O, the shock to my infant eyes, at the emergence of these secreted sisters!  Not only were the tabernacled beings at last revealed, but out of habit!  In identical white nightdress!  Exposing nothing ordinarily not exposed by non-nuns, but … heads bare, when nuns’ heads never were! AND …  shaved? Or maybe, hair just cropped short … for sudden marvel can lead to loss of detail in the most vivid of young memories….

My point here that in Chile geology is not just looked at and walked upon, it happens to you, shocks you … and ultimately shapes you.  You live with the catastrophic volcanic eruptions that now and then happen, here and there, but even more with earthquake—past, present and pending—for they never really stop. You can expect their shock at any moment. You can be dining and see the lamp over the table begin to tremble … a non-event, unless it escalates….

NazcaPlate

And this is true along almost all of Chile’s amazing length, for the geology of the country is created by the clash of two tectonic plates, the Nazca subducting under the South American (as depicted at the right). This creeping titanic collision is what created the Andes in the first place, and continues to reshape them. This subduction also created Chile’s volcanoes, and generates its earthquakes.

Below is a depiction of Chile’s earthquakes as circles, diameter indicating severity, color indicating depth.  One notes that earthquakes stop where the Nazca plate ends, so that the extreme south of Chile is relatively free of temblors.  One also notes that earthquake depth is proport