Earthquake Catalog Search Help

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Select earthquake catalog and output map

There are currently 3 earthquake catalogs available for the online search.

ANSS/CNSS catalog, from 1898 to the present.
Composite earthquake catalog from the ANSS
NCSN catalog, from 1967 to the present.
Earthquakes located by the USGS NCSN.
UCB catalog, from 1910 to the present.
Earthquakes located by the UC Berkeley Seismological Laboratory.

For the experimental version of this search with mapping, we currently only offer one form of output - the readable catalog format. This format is an easy-to-read table in a uniform format containing the basic event information, such as time, epicenter, depth, magnitude, # of stations, azimuthal gap, etc. This is the most readable output, and should be used for all preliminary searches. This is the same for all the catalogs.

Full documentation on the catalog formats is available online.

The user may select from one of four different maps to display the earthquakes: Global, USA, Northern California, San Francisco Bay Area. The maps fixed and are not scaled to the output of the search.

Select earthquake parameters

The earthquake catalogs may be filtered using several different parameters including time, location (latitude and longitude), magnitude, and depth. Additional criteria are available.

Date,Time parameters
All time in the earthquake catalog is referenced to UTC. Date and time parameters can be specified in one of several formats:
- yyyy/mm/dd,HH:MM:SS
- yyyy.doy,HH:MM:SS.
where:
- yyyy = year (1900-present)
- doy = day-of-year (1-366) >li>mm = month (1-12)
- dd = day-of-month(1-31)
- HH = hour (0-23)
- MM = minute (0-59)
- SS = second (0-59.9999)
The date must be fully specified. The time is optional, and defaults to midnight if not specified. There cannot be any blanks between the date and time, or within the date,time string. The year MUST completely specified, eg 1999, not 99.

Select output mechanism

In this version of the catalog search, output is returned to the browser.

Line Limit: In this version of the catalog search, output is limited to 5,000 lines. This limit is to prevent problems such as trying to plot every earthquake in catalog.

Northern California Earthquake Data Center
215 McCone Hall, UC Berkeley
Berkeley CA 94720-4760

www@ncedc.org