Naked Science Forum
Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: Steelycascade95 on 29/11/2012 19:25:07
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This topic is for the discussion of the effect of plate tectonics on the NY NJ area. I've been studying the area for awhile now and want others to opinionate and help me further my research. Post anything related to it below. I live in West Harrison, a suburb of Westchester county about 20 KM from NYC so I've been developing multiple scenarios and timeframes for a damaging event to occur. So what do you think?
And if you didn't know before I know a lot more than basic tectonics and have gone so far as to form my own theorys. I'm talking about research on nearby faults affected by intraplate stress. Faults may include such as the Ramapo Fault, the Dobbs Ferry Fault, the 125th Street Fault, the Dyckman Fault, the Molushu Parkway Fault, and the hypothetical Hartsdale Fault. These are all minor fault zones with miniscule power compared to New Madrid or the San Andreas, but have the potential to release moderatly sized 5-6.5 earthquakes in the near future. According to NYCEM or New York Center For Earthquake Loss And Migitation a light to moderate 5-5.5 earthquake alone would register VII or VIII on the mercalli intensity scale and potentially cause more than 10 billion in damage. A repeat of the 1884 event would be about that bad, and we are overdue for a repeat as the frequency for quakes 5-5.9 here are once every 100-125 years. Look up August 10th 1884 Sandy Hook Earthquake.
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The US Geological Survey has a good record of earthquakes, updated within hours of new earthquakes ocurring: http://earthquake.usgs.gov/earthquakes/map/
This map has a red line which shows the tectonic plate boundaries where most (but not all) of the major earthquakes occur. One runs down the length of California, but the nearest to New York is the mid-Atlantic ridge.
This suggests that Tsunamis rather than earthquakes are the biggest risk to New York/New Jersey.
You can drag the map to center on New York, and use the slider to zoom into the area of interest. By selecting the "US Hazard" from the "Map Layers" menu, you can see that while this area has a slightly elevated earthquake hazard, it is nothing like California, parts of Quebec or the area north of Memphis.
Selecting "All Earthquakes, 30 days", you can see that earthquakes are fairly common in the hotspots, but not around New York.
USGS also has long-term historical maps, if you explore their website.
PS: A paper on the Virginia earthquake last year - it was felt over a wide area...
http://www.usgs.gov/newsroom/article.asp?ID=3447
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A worldwide map of earthquakes over 35 years is hown here: http://en.wikipedia.org/wiki/File:Quake_epicenters_1963-98.png
There are some around Eastern USA.
The mid-atlantic ridge is a narrow spreading zone in a thin oceanic crust, which shows up as a thin line of earthquakes.
This has a very different pattern than subduction plate boundaries where the crust plunges under a continent, producing a thick crust and a wide zone of earthquakes. Along with plate boundaries which grind past each other, these are more likely to get "stuck", and release considerable energy in a massive earthquake.
So New York is relatively safe from known earthquake sources.
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Back to the wikipedia page List of tectonic plates (http://en.wikipedia.org/wiki/List_of_tectonic_plates)
There is this chart:
http://en.wikipedia.org/wiki/File:Plate_tectonics_map.gif
Much easier to read at "full resolution".
It is showing a "major active fault" and a "fault line" following the Appalachian mountain chain along the Eastern USA, and Southeast Canada. There also appears to be another fault line along the Mississippi river through the midwest USA.
A similar question was asked on TNS earlier:
http://www.thenakedscientists.com/HTML/content/latest-questions/question/3174/
http://www.thenakedscientists.com/forum/index.php?topic=41408.0
And BASS suggested looking at Intraplate Earthquakes (http://en.wikipedia.org/wiki/Intraplate_earthquake[/url)