Tuesday, August 23, 2011

S, P, and Tropical Cyclone Waves -OR- An Earthquake (and Maybe a Hurricane) in Washington, D.C.

The seismograph at the Tellus Science Center in Cartersville, Ga., records the magnitude 5.8 earthquake that struck near Mineral, Virginia and jolted the Washington, D.C., area and was felt from Maine and southern Quebec to the Georgia. Source: here.


Wow -- that was wild and more than a little scary.

The almost unheard-of 5.8 earthquake that struck central Virginia near the town of Mineral sent a 30-second jolt through the Washington, D.C., area that sent hundreds of thousands of people scurrying from office buildings and ended the work day effectively three hours early. Likewise in New York City where the shaking was less severe but collective post-9/11 traumas are stronger.

Washington Post online headline earlier this evening. The USGS actually reported a magnitude of 5.8.


Oh, and the North Anna Nuclear Generating Station's two reactors -- located in the same Louisa County as the epicenter of the quake -- both shut down and one of the four diesel generators didn't work.

Editorial Comment: If we are ever going to have that long-anticipated "nuclear renaissance", we better make sure the backup generators are workings.

Another Washington Post online headline, Aug. 23, 2011. Again, USGS reported the magnitude as 5.8.


Anyway, I was on the 9th floor of my office building by L'Enfant Plaza when the shaking started at 1:51PM. I was on the phone with someone (in Nebraska) when I started to fell shaking, but initially I thought it was one of the freight trains that pass on the tracks nearby and sometimes causes a mild rocking motion to the building.

However, the shaking kept getting stronger until finally it was actually frightening and I imaged that the building might actually collapse. I had to get off the phone with the person and leave the building -- except I actually logged off and unhooked the laptop and put it in my book bag. Probably not the best way to evacuate a building during an emergency.

A third Washington Post online headline, Aug. 23, 2011.


There were already large numbers of people streaming outside. Eventually, I made it outside -- our building evacuation plan leaves a lot to be desired with a nearly stationary mob trying to go down one of the flights of stairs. I went to another stairwell that wasn't so crowded.

The earthquake struck 5 miles (8km) SSW of Mineral, Virginia at a depth of 3.7 miles (6km). It is the strongest one in Virginia since a 5.9 earthquake (the strongest ever recorded in the state's history) that struck farther to the southwest on May 31, 1897 in Giles County just west of Blacksburg. The one would not have shaken D.C. nearly as much given that it was at least 100 miles farther away.

Above is the information in a JPEG image as a screen capture of the details from the United States Geological Survey, source here.

I'm not sure what is a "centroid moment magnitude" but I don't want to be in a tall office building for a big one.


The crowd gathering on L'Enfant Promenade 10 minutes after the quake, Washington, D.C., Aug. 23, 2011.


Crowds outside L'Enfant Plaza North along the 900 block of D Street, SW, Washington, D.C., 2:06PM, Aug. 23, 2011.


Outside in the brilliant, low humidity 80F sunlight, people had amassed and were standing in groups or wandering, trying to use their cell phones. My cell phone carrier is Verizon and its system was totally overwhelmed -- no outgoing calls and no inbound or outbound text messages. However, somehow my mom managed to reach me and she told me that the earthquake had been felt across much of the East Coast.

Then I got a single message from Kristof saying he had just experienced a small earthquake at the Goddard Space Flight Center in Greenbelt (about 15 miles from L'Enfant Plaza as the S-and-P waves travel).

Walking across the National Mall about an hour after the earthquake with a large crowd of people still standing outside the Smithsonian Castle, Washington, D.C., 2:59PM, Aug. 23, 2011.


There then ensued about 45 minutes of milling around / confusion / uncertainty in the crowd with several of my co-workers meeting up and everyone trying to figure out what to do. An attempt to go back into the building was rebuffed by security with warnings that it was at your own risk.

One of the company managers reached the second in charge at the company on her Blackberry and he gave the OK for folks to go home.

There then ensued a difficult walk in the hottish-feeling sunlight across downtown amid crowds of people and roads filled with snarled, irritated traffic. It started out bad right from the get-go because we couldn't walk under the Forrestal Building. 

The only actual earthquake damage I saw -- a collapsed brick chimney atop a building housing a 7-11 at the corner of 14th St. and Rhode Island Ave., NW, Washington, D.C., 3:37PM, Aug. 23, 2011.


I walked toward home with two of my colleagues. One of them who lives in suburban Maryland ventured onto the Metro at Metro Center. The other got on one of those Bike Share stations near where I live.

Unfortunately, I had the worst "ugly attack" in terms of feeling how I looked -- pudgy, bushy hair, ugly shirt, even more ugly pants, horribly uncomfortable shoes. It was awful and I am sure my co-worker / friend thought I was quite odd. I'm throwing out all those clothes.

Anyway, I finally got home by 4PM-ish.

My building, the Hampton Court (also called the Hampton Courts), all safe and sound after our once-in-a-century or so earthquake in Washington, D.C., in the warm sunlight of an August day, 3:53PM, Aug. 23, 2011.


Come on Irene?

Oh, yeah, about Hurricane Irene, below is the current (5PM EDT) forecasted track from the National Hurricane Center.

This forcasted track shows the hurricane centered RIGHT OVER Wildwood, New Jersey at 2PM on Sunday, Aug. 28 when Gary, Larry and I are supposed to be there. We are supposed to go on Friday and stay until Monday.

The track has continued to shift steadily eastward with landfall now near Cape Lookout, N.C., at the eastern edge of the double-arc (with Cape Fear in the middle) known as Frying Pan Shoals, "Graveyard of the Atlantic."

Here is the 18UTC Aug. 23, 2011 run of the Hurricane Weather Research Forecast (HWRF) nested-grid model image showing the mean sea level pressure (MSLP) and six-hour precipitation for hour 126 valid at 0UTC (8PM EDT) Aug. 29 (28), 2011 showing the hurricane located at its closest point to D.C. -- about 150 miles offshore. This scenario would give DCA very little precipitation.


At this rate, the hurricane will be entirely off the coast on its run by tomorrow's runs. On the one hand, I don't want my one beach trip this summer ruined, but on the other hand, I suspect it is going to be a case where the coastline gets tropical storm to hurricane conditions with 3 to 6 inches of rain, while D.C. has just partly cloudy skies and no precip at all.

Having said that, here is the other tropical guidance model -- the GFDL Hurricane Model (GHM)-nested grid model -- for its 18UTC Aug. 23, 2011 run also showing MSLP and 6-hour precip for hour 126 valid at 0UTC (8PM EDT) Aug. 29 (28), 2011.

This puts the center of the circulation RIGHT OVER D.C. However, this model has been consistently farther west in its track for the past four days.

We'll see.


OK, that's all for now. I plan to update this blog with additional Hurricane Irene info tomorrow or Thursday.


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