Pacific Earthquake

{Note: This post is #9 in a series of 12 where I review what Scientific American magazine has called the “12 Events That Will Change Everything”. See previous posts “Cloning of a Human”, “Machine Intelligence”, “Superconductors”, “Creation of Life”, “Nuclear Exchange”, “Extra Terrestrial Intelligence”, “Extra Dimensions”, “Polar Meltdown” and “False Dichotomy” for more information.}

The Event: The US Geological Survey estimates California has a 99% chance of having a magnitude 6.7 earthquake before 2038. The earthquake in Haiti earlier this year was a magnitude 7.0.

The Impact: An earthquake of this magnitude in California would be big enough to disrupt utilities (gas, electric, water, sewer, communication), damage buildings, and collapse some bridges and overpasses. It is plausible for a larger one to occur causing even more damage, or potentially a tsunami. The fault line could shift as much as 13 metres which would severely impact roads, railways, waterways, and utilities. While there would be extensive damage to the infrastructure, California is fairly well prepared for an earthquake (due to previous quakes) and loss of life would be limited. Haiti was not prepared for an earthquake and over a quarter of a million people died as a result of that earthquake in January.

The Science: The earth is not a solid planet. The surface or crust is between 6km and 35km deep consisting primarily of rock with either soil or water on the top (the crust is thinner under the oceans). Underneath the crust is liquid magma (referred to as lava when it comes out of a volcano) which is essentially molten rock. So the surface is basically floating on a sea of magma. With the earth’s constant rotation, gravitational effects from the moon and sun, and the motion of the magma, there is a continuous force on the earth’s crust. While the crust may be mostly rock, there are weak points and over time, these weak points can’t resist the forces acting on them and they shift a little bit (or a lot). We refer to these weak points as fault lines and when we map the locations of the major fault lines over the planet, we can divide the earth into 7 or 8 major sections called tectonic plates. Most of the big earthquakes happen on or near these fault lines, one of which runs through California. There are about 100,000 earthquakes every year that are large enough to be felt – this gives you some idea regarding how unstable our surface actually is. Of these, only a handful are big enough to cause damage. A big earthquake tends to occur when the fault line hasn’t moved for a long time and the forces acting upon it have built up to the point where the fault “lets go” and significant movement results.

Jac’s Analysis: I agree that this event is very likely and anyone living in areas prone to earthquakes should take some precautions. Most people in developed countries that live in these areas have been advised on how to prepare for an earthquake and what to do when one occurs. This impacts building codes so that new or renovated buildings are designed to withstand quakes. Communities also have plans in place to assist with evacuations, providing food and water, etc. Individuals should have a “kit” ready with bottled water, non-perishable food, flashlights, etc. as earthquakes will often knock out power and communication lines.

Our Reaction? Where I live, the possibility of a major quake is very unlikely, so I’m not too concerned. And when I travel to the west coast of Canada or the US (not very often), I’m usually in newer hotels that have been built to withstand most earthquakes. I think our focus should be on those countries that are not able to prepare for a major quake (like Haiti) and try to figure out how we can help them by sharing our technology (building designs and retrofits) and responding to emergencies.

Questions and comments?

1. Have you ever felt an earthquake? How did you react?
2. Does this change your thoughts about how solid our planet is? Is the earth built on “firm foundations that cannot be moved” Psalm 104:5?

Next week we look at the promise of almost unlimited clean energy through nuclear fusion.

Jac