Thursday, January 28, 2010

Happy PFF - Seismicity of Caribbean

Marie, the French Fractrice, has "Booger Hollow, Arkansans" on her blog for this week's Postcard Friendship Friday, but I picked this one out ahead of time.

An over sized postcard published by the US Geological Survey, it shows the Caribbean and surrounding areas and plotted in tiny dots (even on the original) are the locations or epicenters of 94 years of earthquakes. Coloring of the land indicates height above sea level (green: low elevation; browns: getting higher), and different shades of blue indicate ocean depths. (Pale color: less than 100 meters, deeper blues for deeper depths). The average ocean floor in the Atlantic and Pacific oceans is over 3 miles deep!
There are a number of plate tectonic boundaries in the Caribbean and one does veer right through Haiti. A 7.0 magnitude quake is a major one and in such a poor country..... This area is going to be suffering for years to come. I worry about 6 months from now, when the hurricanes start arriving.
The USGS has prepared a poster on the 7.0 Haiti earthquake. You can print out a large copy if you have access to a large-format printer, or you can print a smaller size. the link is
One person has asked where I find all these postcards. Well, let's just say that if you go to conferences where the state surveys have a booth and they have promotional postcards.... you can build a great collection.

I have two more state geology postcards, for later weeks. Take care!


Thursday, January 14, 2010

Happy PFF - Geology of Connecticut

Welcome to Postcard Friendship Friday, hosted by Marie at the French Fractrice.

This postcard of the bedrock geology of CT came out rather pale, I'm afraid. And, the original is back in my office so I can't walk you through the details!!! I found a few more of these geological postcards buried deep in a drawer, so I have a few more to share with you.

I can tell you that most of the bedrock on the east and west of CT is metamorphic, though of different types and ages, therefore the different colors on the map.

The yellow area with red squiggles in it is the Hartford Basin. This area is interesting for several reasons. According to Gil Hanson, a geologist at SUNY Stony Brook, "The Hartford Basin is one of the many rift basins along the east coast of North America that formed during the early stages of rifting of Pangea during the Triassic and Jurassic. The rifting of Pangea eventually led to the formation of the Atlantic Ocean. The Hartford Basin contains a thick sequence of stream and lake sediments and basaltic sills and lava flows all of which are well exposed."

(To see an animation of the breakup of Pangea, go to this website by Chris Scotese. Move your mouse over the animation on that page, click and hold the left mouse button, and slide your mouse sideways. Cool!)

The red parts are intruded sills and lava flows, now making ridges and hills running down this valley.
The stream and lake sediments in some cases preserved dinosaur footprints. These can be seen at Dinosaur State Park!

Here is something else I found out through Google (how did we live without this?). The Brownstone buildings of NYC and Boston are made from the Portland formation, quarried from this area of Connecticut. According to the website on this formation, "The prevalence of Portland sandstone for construction during this era lead to the term "brownstone" being synonymous with "rowhouse" in the northeastern US."

Would you like a copy of the Generalized Bedrock Geologic Map of Connecticut, in a 8.5 by 11 inch size? Only 25 cents! You may purchase it through the on-line store of the Connecticut Department of Environmental Protection, which also includes the Connecticut Geological and Natural History Survey.

Happy Postcard Friendship Friday!

And please remember the plight of the people of Haiti. That EQ epicenter was very close to Port-au-Prince, the major population center, and Haiti building codes, such as they are, cannot be compared to those of California. This EQ is as big as the Loma Prieta or Northridge EQ's, but much more devastating.

Friday, January 8, 2010

Happy PFF - Washington State Geology

First, I would like to apologize for the quality of this image. I sent this postcard off to a person in Thailand via Postcrossing, before I started this series of blog posts. Thankfully this person put the card up on their postcard wall, where I retrieved this image. So I do not have the card in front of me, to tell you about the details of the geology of Washington.

However: the first page of the teacher resources PDF (published by the WA Dept. of Natural Resources) has a great map. Print it out and brighten up your office!

I can tell you though that the southern and central parts of the state, in various shades of orange and yellow, are underlain by thick layers of Columbia River basalt. This nice graphic from the US Geological Survey explains it well. The eruptions ended 6 million years ago. A rich soil has formed over much of this area, making it great for farming.

Not feeling too well today, so will sign off here. Happy PFF!

Friday, January 1, 2010

Post #75: Happy New year and PFF

Thank you to Marie, for hosting this party at the French Fractice.

For Postcard friendship Friday I have:

A postcard dated Jan. 1, 1913, postmarked Los Angeles.

Dear Son,
All are well. was down to Pasadena today to see the floral Parade Uncle Jim aunt and Charlie went with us so warm we sweat. ??? ate their dinner on the ground and lay and slept on ground. write 1228 Ingraham St. Los Angeles CA - Mamma"

Well, I knew the Tournament of Roses parade had been around for a long time, but I did not know how long. First started in 1890, in 1895, the Tournament of Roses Association was formed because it was getting to be a big event.

And the joy of Google Maps: 1228 Ingraham St is now a parking lot one block from Good Samaritan Hospital, and a few blocks from the 110 interstate. I bet it was a trim single family house on a quiet street in 1913.

(Just back from a family holiday)


Related Posts with Thumbnails