All Shook Up

By Margo D. Beller

@MargoDBeller

Around 3:30 on the morning of Friday, Aug. 14, one of my friends told me, she was rudely awakened by what she thought was an explosion. In that addled state between waking and sleeping, she thought it was construction work.

She wasn't alone, according to the reports I read on NJ.com. In fact, it was a 2.5-magnitude earthquake. Luckily, no one reported any damage.

The quake's epicenter, according to the U.S. Geological Survey, was two miles north-northeast of Bernardsville, where my friend lives and where the headquarters of New Jersey Audubon and its Scherman Hoffman sanctuary are located. According to one report I read, the earthquake was "centered two miles underground about three miles northwest of Olcott Square, near the banks of the Passaic River in the Hardscrabble section near the Scherman-Hoffman Wildlife Sanctuary and the Morristown National Historical Park" informally known as Jockey Hollow.

Scherman Hoffman

Scherman Hoffman (seen at left) is in Somerset County, across the Passaic River from Morris County. According to local media, the Morris County Office of Emergency Management almost immediately started getting 911 calls from a number of towns, including some very close to mine.

The USGS said it received more than 200 reports from as far southwest as Philadelphia and as far north as Rochester, N.Y.

Who knew Scherman Hoffman could be Ground Zero of an earthquake?

As for me, I slept through it. It was, after all, "only" a minor earthquake.

Earthquakes were not part of my childhood in the east. Nor'easters, yes. Heavy snow, yes. Even the occasional hurricane.

However, I think we're going to hear more about damaging earthquakes in the U.S. thanks, in part, to a burgeoning population that has moved to housing put up on just about any land mass no matter how tiny or ecologically insecure.

One of the worst series of earthquakes to hit the eastern U.S. centered on the New Madrid Fault, named for the epicenter in New Madrid, Mo., between 1811 and 1812. The San Andreas fault, the cause of the San Francisco earthquakes of 1906 and 1989, is better known. It's even been the subject of a 2015 movie.  

But the New Madrid, at 7.3 to 7.5 on the Richter scale, was the most devastating earthquake to hit the U.S. for its time.

There are faults and folds all over the U.S. and the world. New Jersey's fault is the Ramapo Fault System. What shook Bernardsville and beyond was described as an "offshoot" of the fault.

The Ramapo Fault is part of a system of faults that runs from southeastern New York to eastern Pennsylvania. According to a 2004 fact sheet I found from Columbia University, these faults were active "during the evolution of the Appalachians, especially in the Mesozoic when they served as border faults to the Newark Basin and other extensional basins formed by the opening of the Atlantic Ocean approximately 200 million years ago."

(If you want to learn more about the Ramapo Fault click here.)

So here we are in the New York City metropolitan area, which is now much more built up than New Madrid was in 1811.

My husband remembers a visit to his parents in N.J., in the late 1980s, when an earthquake struck and he was shaken awake by the sound of thunder with an edge. He called it "thunder on drugs."

I remember an August 2011 earthquake while at work when there was a violent shake and a crash, as though someone on the floor below me had dropped a heavy piece of equipment. This earthquake was centered not far from Washington, D.C., and was so strong it damaged the Washington Monument.

According to NJ.com, there have been a number of "minor" earthquakes in New Jersey since 2010 measuring anywhere from 1.2 to 2.1 on the Richter scale.

Should we be getting used to more frequent rumbling of terra not-so firma? And what will happen when the Big One strikes a major urban population such as New York?

Well, Hurricane Sandy in 2012 gave us a pretty good indication of what happens when a big city is hit by the Big One, and that was a case when reports of Sandy's strengths were known days in advance.

Now imagine a major earthquake, say a 6 ("noteworthy" on the Richter scale) or 7 ("high" - the 1989 San Francisco area quake was a 6.9).Scherman sign Like my friend's rude awakening, there are no warning signs. The earth starts shaking. It could be a tremor or more violent. It could last a few seconds, it could last minutes. There could be a pause and then, when you think it's over, aftershocks (which could come hours later and be worse than the original earthquake).

Your world, literally and figuratively, could come crashing down around you. It could happen at any time.

Scientists recently did tests to see what would happen if the New Madrid fault took place today.

Based on the simulations, were the 1811-1812 earthquakes to take today - and remember, these were over 7 in magnitude - more than 8 million people (emphasis mine) living and working near the New Madrid seismic zone "would experience potentially damaging ground shaking" at intensities ranging from strong to severe, according to the lead author of the paper that appears in the July 30, 2015, edition of the Bulletin of the Seismological Society of America.

This is no movie where the world ends and then the house lights come up. What happened in Bernardsville could be looked at as a coming attraction..