Make no mistake: earthquakes are scary. Earthquakes are dangerous. And there have been a lot of them lately. In addition to the one felt all along the East Coast that struck Mineral, VA, on August 23rd, there was a second one in Colorado with a magnitude of 5.3, and a third one with a magnitude of 2.9 four days later in upstate New York.
Needless to say, this has a lot of people on the East Coast terrified, especially since Irene struck a week later, and aftershocks of the Mineral quake were being felt for a while after. But they shouldn’t be scared: here’s why.
#5) As Californians Will Be Happy to Tell You, a 5 is Fairly Minor
People are often fooled by the Richter scale. We generally view things on a linear scale, you know, rate something one to ten. So they see a 5 is fairly close to a far more dangerous 6 or 7, and wonder what’s going on.
Nothing: the Richter scale isn’t linear, it’s logarithmic. For those of you who are bad at math, it’s simple: a two is ten times more intense than a one, a three is ten times more intense than a two, and so on. So, a six on the Richter scale is ten times more intense than a five.
This is part of the reason the number of fatalities from all these earthquakes number precisely 0.
#4) Colorado Isn’t Unfamiliar with Earthquakes
Colorado gets earthquakes on a relatively regular basis: its last round of quakes was in 2001. But it’s limited to one part of the state: west of the Rockies. In fact, some parts of the state are considered “aseismic”, that is, there’s absolutely nothin’ going on there earthquake-wise. What the nightlife is like we haven’t investigated.
But Colorado’s history of earthquakes extends back to at least the 1870s, which is when we started tracking data, and only one has been about 6 on the Richter scale. So, while it’s a bit odd, an earthquake there isn’t unprecedented.
#3) Colorado, Virginia, and New York All Share the Same Tectonic Plate
The massive earthquakes in California are not caused by angry earth demons or smog monsters getting restless; they’re caused by the fact that the North American Plate and the Pacific Plate rub up against each other in about 810 miles of California.
The rest of the US? Not so much. In fact, the closest plate to us besides the Pacific, geographically, is the Caribbean plate. You might remember the catastrophic earthquake in Haiti: that was caused by the North American and Caribbean rubbing together. The closest plate to the East Coast? The Eurasian and African, which meet…smack dab in the middle of the Atlantic Ocean, far, far away from any major settlements.
So that apocalyptic grinding that destroys California periodically? Yeah, we’re far, far away from that, and always will be.
#2) It Was Felt So Far Because Virginia Is So Stable
A 5.8 is pretty unusual…but Virginia gets its share of quakes. A 2.5 struck in 1997, and Charlottesville got surprised by a 3.2 in 2001.
But mostly the reason it was felt all along the East Coast was because Virginia is just so darn stable. It’s mostly the geological equivalent of a well-paved driveway: smooth, flat, and tightly connected. There are one or two cracks: Virginians know them as the James and New Rivers, respectively. But by and large, it’s steady and even.
But this means energy transfers through it easily, since it’s so well connected. So when a 5.8 struck, the energy emanated all up and down the East Coast. Ironically, what you felt was just the earth showing it communicates energy really well.
#1) Earthquakes? Not that Rare
You might have guessed we’re building to this one: earthquakes are not as rare as you think. Don’t believe us? Here’s a USGS real-time updated map. You might notice these quakes tend to A) be centered along fault lines and B) none of them have made the news.
There’s a reason for that: most earthquakes are incredibly minor. Keep in mind that logarithmic scale; if some people barely felt a 5…imagine how little the earth moves for a 1.
The problem isn’t with the plate, it’s with our perceptions. We’re so used to the earth being steady, stable and immovable that we don’t notice instead that it’s constantly, almost imperceptibly shifting, all the time. The Earth is stable, but it’s dynamic, moving constantly.
In short, the Earth is safe under our feet…but it changes just like we do. And you have to admit: that’s kind of awesome.
By Dan Seitz