Shakemap Product Formats
Maps
JPEG
JPEG (which stands for Joint Photographic Experts Group, the standards body that created it) is a 24-bit, platform-independent image and graphics format. This format can be viewed in any web browser, and can be manipulated by most image-production applications. The compression scheme is "lossy" though, so multiple generations of editing and saving will degrade the image.
Postscript
A language to describe graphics independently of the resolution of the output device. Printers with Postscript drivers will rasterize these printer files to high-quality map plots. If the Postscript file name ends with '.zip,' the file has been compressed with the Zip utility and will need to be unzipped before it can be used.
8-1/2 x 11
Postscript file with map sized to print on 8.5" x 11" paper.
Poster
Postscript file with map sized to print on a poster printer (approximately 32" x 28"). This file is only available for larger earthquakes.
PDF
Portable Document Format. Can be viewed and printed with the free Adobe Acrobat Reader. More information about Acrobat and a software download site are available http://www.adobe.com/products/acrobat/readstep.html. This file is only available for larger earthquakes.
Media Maps
General
The Media Maps are simplified versions of the Instrumental Intensity maps (PostScript and JPEG format, see above). While the intensity information they contain is exactly the same as that in the other maps, they are packaged in a way that makes them more suitable for broadcast to low-resolution devices, such as TV monitors: roads and borders are thicker, fonts are larger, and the title and intensity scale are simplified.
Decorated
Shows state borders, map title, simplified intensity scale, and the intensity overlay. Includes some city names, major freeways and a distance scale.
Bare
Shows only state borders, latitude, longitude, and the shaking intensity.
Info Sheet
Intended to supplement the Media Maps, the Info Sheet is a text file that provides basic event information, organizational credits, contact information, and information about earthquake intensities and ShakeMap.
Raw Grids
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Text X, Y, Z Values
Values of the peak amplitudes at the ShakeMap map grid nodes. File is ASCII text in the following format:
First line is a header with:
<name/CUSPID of event> <mag> <epicentral lat> <epicentral lon> <MMM DD YYYY> <HH:MM:SS timezone> <W bound> <S bound> <E bound> <N bound> (Process time: <time>) <Location String>
The first 'time' field is the time of the event.
'Process time' is the time this file was last updated.
ex:Northridge 6.7 34.213 -118.5357 JAN 17 1994 04:30:55 PST -119.1857 33.7775 -117.857 34.6485 (Process Time: Wed Nov 4 17:25:18 1998) Northridge Earthquake
For large or historic earthquakes the "Location String" will usually be the name of the earthquake, otherwise it will be something of the form "12.1 mi. SSW of Carpinteria, CA"
The remaining lines are of the form:
<lon> <lat> <pga> <pgv> <mmi> <psa03> <psa10> <psa30>
psa03 = spectral acceleration at 0.3 s period, 5% damping.
psa10 = spectral acceleration at 1.0 s period, 5% damping.
psa30 = spectral acceleration at 3.0 s period, 5% damping.
For pga value == (percent-g)
For pgv value == (cm/s)
For mmi value == Intensity
For psa value == (percent-g)
If the grid file name ends with '.zip,' the file has been compressed with the Zip utility and will need to be unzipped before it can be used.
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XML
IMPORTANT NOTE: The ShakeMap XML format is a prototype that is still under development. At this time we are distributing it to solicit input for revisions to the schema. Please use the comment form to provide feedback or contact one of the ShakeMap developers directly. If you are considering developing an application that uses the ShakeMap XML, please use the comment form to contact us so that we may advise you on the current status of the schema and the areas likely to be revised.
Supplies values of the peak amplitudes and other parameters at the ShakeMap grid nodes. Schemas are available at http://earthquake.usgs.gov/shakemap/xml/schemas. The following is a brief summary of the format:
<shakemap_grid event_id= shakemap_id=(currently the same as the event id) shakemap_version=(integer indicating map revision) code_version=(string indicating the version of the shakemap software) process_timestamp=(yyyy-mm-ddThh:mm:ssZ) shakemap_originator=(network id code) map_status=(RELEASED|REVIEWED|CANCELLED) shakemap_event_type=(ACTUAL|TEST|SCENARIO|HEARTBEAT) > <event magnitude= lat= lon= event_timestamp= event_description= > <grid_specification lon_min= lat_min= lon_max= lat_max= nominal_lon_spacing= nominal_lat_spacing= nlon= nlat= /> <grid_field index=n name=m units= /> + <grid_data> CDATA </grid_data> </shakemap_grid>'+' indicates that multiple tags of this type are expected
The 'grid_specification' tag defines the grid boundaries, and also provides the approximate interval between grid points (beware roundoff) and the number of grid point in the latitude and longitude directions.
In the grid_field, the index gives the column number of the associated parameter. The current names for the parameters are:
LAT = latitude (decimal degrees, north)
LON = longitude (decimal degrees, east)
PGA = peak ground acceleration (percent-g)
PGV = peak ground velocity (cm/s)
MMI = instrumental intensity (Modified Mercalli Intensity units)
PSA03 = spectral acceleration at 0.3 s period, 5% damping (percent-g)
PSA10 = spectral acceleration at 1.0 s period, 5% damping (percent-g)
PSA30 = spectral acceleration at 3.0 s period, 5% damping (percent-g)
SDPGA = standard deviation of peak ground acceleration (percent-g)
SVEL = Shear wave velocity (Vs30) at the site (m/s)
The current units are:
dd = decimal degrees
pctg = percent 'g' (i.e., percent of the nominal gravitational force at the Earth's surface)
cms = centimeters per second
ms = meters per second
mmi = Modified Mercalli Intensity
Following is an example of a (truncated) ShakeMap XML file:
<?xml version="1.0" encoding="US-ASCII" standalone="yes"?> <shakemap_grid event_id="14138080" shakemap_id="14138080" shakemap_version="7" process_timestamp="2005-12-19T16:07:03Z" shakemap_originator="ci" map_status="RELEASED" shakemap_event_type="ACTUAL"> <event magnitude="5.2" depth="10.29" lat="35.027200" lon="-119.178300" event_timestamp= "2005-04-16T19:18:13GMT" event_description="13.4 mi W of Wheeler Ridge, CA "/> <grid_specification lon_min="-120.428300" lat_min="34.193866" lon_max="-117.928300" lat_max="35.860533" nominal_lon_spacing="0.016667" nominal_lat_spacing="0.016667" nlon="151" nlat="101"/> <grid_field index="1" name="LON" units="dd"/> <grid_field index="2" name="LAT" units="dd"/> <grid_field index="3" name="PGA" units="pctg"/> <grid_field index="4" name="PGV" units="cms"/> <grid_field index="5" name="MMI" units="mmi"/> <grid_field index="6" name="PSA03" units="pctg"/> <grid_field index="7" name="PSA10" units="pctg"/> <grid_field index="8" name="PSA30" units="pctg"/> <grid_field index="9" name="SVEL" units="ms"/> <grid_data> -120.428300 35.860533 0.0764 0.0554 1.0000 0.0371 0.0492 0.0106 464.0000 -120.411633 35.860533 0.0941 0.0794 1.0000 0.0439 0.0657 0.0141 301.0000 -120.394967 35.860533 0.0921 0.0735 1.0000 0.0419 0.0576 0.0123 372.0000 ... </grid_data> </shakemap_grid>
IMPORTANT NOTE: Not all parameters are guaranteed to be present in any given file. For example, the pseudo-spectral acceleration values are only produced for earthquakes of larger magnitude, typically M5.0 and up. Also, the order of elements may vary from region to region or even from map to map. Automatic processes should always consult the "grid_field" tags to obtain a list of the available parameters and their order in the grid. We reserve the right to add parameters at any time without notice, and we will almost certainly exercise this right.
GIS Files
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HAZUS ZIP File
Contour polygons of the average ground motion amplitudes in ArcView shape files. Please note that these are average ground motions, whereas most ShakeMap amplitudes are given as peak. Average ground motions are 15% less than peak.
This is an archive of files (three files for each of the mapped parameters) compressed in zip format.
The three files are:
- .dbf = A DBase file with layer attributes
- .shp = The file with geographic coordinates
- .shx = An index file
These shape files are designed with intervals that are appropriate for use with the HAZUS software, though they may be imported into any GIS package that can read ArcView shapefiles. Because HAZUS expects PGV in inches/sec, and all amplitudes to be average, not peak, this file may not be suitable for all applications; see "Shape Files" below for another set of shapefiles with peak amplitudes and more generally useful units.
The contour intervals are 0.04g for PGA and the three spectral acceleration parameters (only two of which are used by HAZUS), and 4 inches/second for PGV. The file also includes MMI contour polygons in intervals of 0.2 intensity units.
The HAZUS GIS files are only generated for events that are larger than (approx.) M5.0.
If you are unfamiliar with using shape files to run HAZUS, see the tutorial.
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Shape Files
High-resolution contour polygons of the peak ground motion parameters in ArcView shape files. This is an archive of files (three files for each of the mapped parameters) compressed in zip format.
The three files are:
- .dbf = A DBase file with layer attributes
- .shp = The file with geographic coordinates
- .shx = An index file
These shape files are intended for use with any GIS software that can read ArcView shape files. Note, however, that the PGV contours are in cm/s, and are therefore NOT suitable for HAZUS input.
The contour intervals are 0.04g for PGA and the three spectral acceleration parameters (only two of which are used by HAZUS), and 2 cm/sec for PGV. The file also includes MMI contour polygons in intervals of 0.2 intensity units.
shape.zip is available for all events, but the spectral values are only included for earthquakes of magnitude 5.0 and larger.
KML
KML is an XML file format used by Google Earth (http://earth.google.com). Once you have downloaded and installed Google Earth, you can download the event .kml file and import it to Google Earth. You will be able to view the intensity map overlaying topography and aerial photographs, chage the transparency, turn on or off a layer with clickable station information, zoom in or out, rotate the map in three dimentions, etc.
Station Lists
Text
A table of earthquake and station parameters, formatted to be read easily by humans. An XML formatted file is also available, and is the best option for parsing the information by computer.
The earthquake information includes: CUSP ID, magnitude, date, time, epicenter coordinates and depth.
The station information includes name and/or code, location coordinates, and peak velocity and acceleration values.
Stations may be flagged to indicate they were not used in the ShakeMap processing. The types of flags are indicated at the bottom of the list.
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XML
A table of earthquake and station parameters, tagged in XML format for parsing by computer. The DTD defining the structure of the XML flags is incorporated in the file.
The earthquake information includes: CUSP ID, magnitude, date, time, epicenter coordinates and depth.
The station information includes name and/or code, location coordinates, and peak velocity and acceleration values.
Stations may be flagged to indicate they were not used in the ShakeMap processing. The types of flags are indicated at the bottom of the text version of the station list.
For more information on XML and XML parsers, see the XML page of the World Wide Web Consortium.
Metadata
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FGDC Metadata
These files are provided to comply with the Federal Geographic Data Committee standards for geospatial metadata. Information regarding the standards can be found at the FGDC website. See also:
Federal Geographic Data Committee. FGDC-STD-001-1998. Content standard for digital geospatial metadata (revised June 1998). Federal Geographic Data Committee. Washington, D.C.
The metadata are provided in text, HTML, and XML formats.
