The David Rumsey Collection, the fantastic online resource for digitized historic maps, has recently scanned and made available a 1905 Sanborn fire insurance atlas of the City of San Francisco. The atlas is very valuable resource for many reasons, thogh specifically beccause it dates to just months before the historic 1906 earthquake and fire that destroyed a large portion of the city.

The original atlas belongs to the San Francisco Public Library's San Francisco History Center. You can read more about the atlas on the David Rumsey Collection blog and view the pages themselves at the David Rumsey Collection site.

ChangeMatters is a new service created by Esri to allow users to quickly and easily compare bands of satellite imagery directly in a web browser. Using Landsat Global Land Survey (GLS) imagery from 1975-2000, Esri has created a service that allows users to "Use the best continuous source of earth monitoring data to visualize and analyze change." The service is also a layer package on ArcGIS Online which allows users to take advantage of the online imagery storage via ArcGIS as well.

ChangeMatters is a collaboration between Esri, the USGS, Kass Green and Associates (KGA), Tukman Geospatial, and DTSAgile.

WeatherSpark allows users to view historical weather data for over 4,000 weather stations around the world. The site is in beta and includes mostly in METAR format with Mesonet and PWS on the horizon.

From the WeatherSpark site: "WeatherSpark is a new type of weather website, with interactive weather graphs that allow you to pan and zoom through the entire history of any weather station on earth. Get multiple forecasts for the current location, overlaid on records and averages to put it all in context."

An 8.9 magnitude earthquake struck near Sendai, Japan, off the east coast of Honshu, on March 11, 2011. The earthquake created a tsunami that has moved across the Pacific Ocean to the west coast of the mainland United States.

There are a number of resources already available for the earthquake and tsunami:

Google Crisis Response

USGS Earthquake Hazards Program

OpenStreet Map

The Map Room blog

Esri distaster response

Berkeley Seismological Lab's Seismo Blog

The essential lesson from the Japan earthquake for the U.S. from UCB Professor Richard Allen in Scientific American

Japan earthquake: The explainer from Chris Rowan, UC Chicago

Japan Meteorological Association

Via BoingBoing: Here's a short video demonstrating the phenomenon of liquefaction, the process by which soil loses strength and stiffness caused by an earthquake and behaves like a liquid. The liquid rises to the top of the seemingly solid soil and remains unabsorbed, creating, as the narrator notes, unstable ground after the earthquake has subsided.

This footage is from Christchurch, New Zealand, but large portions of the soil in the San Francisco Bay Area are susceptible to this type of reaction to sudden changes in pressure or stress.