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What's New at Arcadia

Historic Burial Grounds of the New Hampshire Seacoast By Glenn A. Knoblock

Arcadia Publishing has releases a new title in the Images of America series, the historic account of the cemeteries along the New Hampshire Seacoast. This collection is a must for anyone interested in local history, genealogy, or colonial-era art. Please visit Arcadia Publishing to purchase your copy of Historic Burial Grounds of the New Hampshire Seacoast and browse other cemetery books!

Green-Wood Cemetery By Alexandra Mosca

Arcadia Publishing announces the release of the historic account of one of New York's most famous cemeteries. Aracdia Publishing's Images of America series has an extensive catalog of many cemetery publications! Please visit Arcadia Publishing to purchase your copy of Green-Wood Cemetery.

Announcements

Quoting Death in Early Modern England: The Poetics of Epitaphs Beyond the Tomb By Scott L. Newstok

An innovative study of the Renaissance practice of making epitaphic gestures within other English genres. A poetics of quotation uncovers the ways in which writers including Shakespeare, Marlowe, Holinshed, Sidney, Jonson, Donne, and Elizabeth I have recited these texts within new contexts. Visit Palgrave Macmillan and purchase your copy today!

Living by the Dead By Ellen Ashdown with illustrations by Mary Liz Moody.

A memoir about living beside a cemetery--and about the members of my family who came to rest at Roselawn Cemetery in Tallahassee, Florida. Please visit Kitsune Books for more information.

Graveyards of Chicago: The People, History, Art, and Lore of Cook County Cemeteries By Matt Hucke And Ursula Bielski.

Discover a Chicago That Exists Just Beneath the Surface - About Six Feet Under! Take a tour of Chicago's permanent residents! Please visit the Lake Claremont Press website to purchase your copy of Graveyards of Chicago today!

Epitaphs: The Magazine for Cemetery Lovers By Cemetery Lovers

For information regarding subscriptions, single issues, submission guidelines, deadlines, classifieds or advertising for future issues, please visit The Cemetery Club.

Guardians of the Soul: Angels and Innocents, Mourners and Saints with photography by John Bower and foreword by Claude Cookman

Indiana's remarkable cemetery sculpture is now available. Please visit Studio Indiana for more information.

West Springfield Massachusetts: Stories Carved in Stone by Rusty Clark

Features information on early New England gravestone carvers with more than two hundred photos and illustrations. Please visit the Dog Pond Press website.

Crumbled Tombstones Lead to New View of 1906 Earthquake PDF Print E-mail
Tuesday, 24 January 2006
By Michael Schirber
LiveScience Staff Writer

The great San Francisco earthquake of 1906 was the deadliest in U.S. history. A new map of the event, based in part on crumbled tombstones, shows in detail the extent of ground rumbling and provides lessons for future events.

On the morning of April 18, 1906, an earthquake of approximate magnitude 7.8 erupted, with an epicenter near the where the Golden Gate Bridge would later be built. It was felt 400 miles away in Los Angeles and in Winnemucca, Nevada. Damage was heavy in the farming community of Ferndale, Calif., 200 miles to the North.

"Many of our most solid and substantial buildings have been reduced to almost a wreck," was the report in the April 20, 1906 edition of The Ferndale Enterprise.

The impact was greatest in San Francisco where a fire, triggered by the quake, ravaged much of the city. More than 3,000 people died, and damage exceeded 400 million dollars.

Model for the present

Much scientific investigation followed. Geologists witnessed for the first time large ground slips all along the 300-mile-long rupture. Theories were devised to explain these horizontal shifts.

"Our present model for what causes earthquakes came out of the 1906 earthquake," geologist John Boatwright told LiveScience.

Continuing with this legacy, Boatwright and Howard Bundock, both from the U.S. Geological Survey (USGS), have re-analyzed the old data and added more numbers to create a detailed map of the 1906 event. The ShakeMap, as it is called, will give earthquake researchers a template for refining their models of big earthquakes.

"This ShakeMap graphically points out that great earthquakes like 1906 behave in ways that are very different than a smaller magnitude event," Boatwright said.

Subjective measure

ShakeMap is a relatively new tool for characterizing the intensity of an earthquake. Intensity is a qualitative measure of the amount of shaking at a particular point on the Earth's surface. It is separate from the magnitude, which is an overall measure of an earthquake's energy.

Intensity is usually based on subjective experience.

The USGS mails out questionnaires or has people fill out a web survey to determine the shaking that was felt in a particular area. A full intensity assessment can take a long time to compile.

The ShakeMap, however, takes only a few minutes. It involves computer models that use data from modern seismic networks to generate the expected intensity. For earthquakes greater than magnitude 3.5, a ShakeMap is immediately sent out to first responders and earthquake scientists.

1906 vs. Loma Prieta

For the 1906 earthquake, Boatwright and Bundock have basically done a ShakeMap in reverse. Since there is very little instrument data from back then, the researchers "retrofit" the map software to incorporate historical accounts, newspaper clippings and a new analysis of damage to tombstones of the time.

This new look at the 99-year-old event makes it clear that the intensity of a great earthquake cannot be predicted by simply turning up the magnitude of a smaller earthquake, like the magnitude 7.1 Loma Prieta earthquake that struck in the same vicinity on October 17, 1989 and halted the third game of the World Series.

"If you make the assumption that the 1906 is something like lining up 20 or so Loma Prietas," Boatwright said, "you expect more shaking along the fault than was actually measured."

While places near the fault experienced lower intensities than might be expected, the 1906 ShakeMap also shows that spots away from the fault had slightly higher intensities. Deciphering this distribution of shaking is important for geologists because there is a dearth of good data on strike-slip earthquakes, of which 1906 is one with magnitudes around 8.

Dead ringer

One of the most interesting ways geologists have measured the intensity of the 1906 earthquake is by visiting rural cemeteries.

"What tended to happen is the tombstones broke," explained Boatwright, who made several trips to cemeteries that previous surveyors had overlooked.

If Boatwright saw one or two pre-1906 headstones with damage, he assumed the area had felt an intensity of VII (or 7 in regular numbers) on the Modified Mercalli Intensity Scale. If a quarter to a third of the headstones were broken, the site was given a VIII (8), while anymore than that was a IX (9).

In Bloomfield, Calif., Boatwright was amazed to find three flat-lying footstones that were damaged. He gave that a 9.

Boatwright said he enjoyed this work, but "I'm hoping my cemetery tours are over."

http://www.livescience.com/forcesofnature/050422_earthquake_1906.html
 
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