Map of macroseismic intensity.

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.

Large format map of macroseismic intensity suitable for television broadcast.

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

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.

XML

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=
                            nominal_pga_std=(The standard deviation of PGA as given by the attenuation relation (i.e., "regression") used.  
                                            The units are natural log of percent-g.) />

                        <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)
STDPGA = the standard deviation of PGA at the point (natural log of percent-g)
URAT = the ratio of the standard deviation of PGA at the point to the standard deviation of the GMPE (see "nominal_pga_std" above) (no units)
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="STDPGA" units="pctg"/>
                    <grid_field index="10" name="URAT" units=""/>
                    <grid_field index="11" name="SVEL" units="ms"/>
                    <grid_data>
                    -119.7857 35.0463 5.28 5.51 4.54 13.1 6.89 1.28 0.45 1 372
                    -119.7774 35.0463 5.32 5.53 4.75 13.17 6.91 1.28 0.45 1 372
                    -119.7690 35.0463 5.36 5.55 4.75 13.25 6.93 1.29 0.45 1 372
                    ...
                    </grid_data>
                    </shakemap_grid>
                    

The structure of the uncertainty.xml file is nearly identical to grid.xml, but the values contained therein are the standard deviations of the ground motions for each parameter. These uncertainties (except for intensity) are given in natural log units so that, for example, one standard deviation in ground motion is given by (ln(PGM) +/- STDPGM), where PGM is the ground motion and STDPGM is the standard deviation value from the grid. The uncertainty for intensity is in linear units, so one standard devaition is given by (MMI +/- STDMMI).

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.

Description for Geographical Information System (GIS) Files used.

HAZUS ZIP File

Contour polygons of the average ground motion amplitudes in ArcGIS 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 ArcGIS 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.

Shape Files

High-resolution contour polygons of the peak ground motion parameters in ArcGIS 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 ArcGIS 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 acceleration values are typically 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.

ESRI Raster Files

Binary grid files in ESRI raster format (see here for information on converting to and from raster format in ArcGIS). This is an archive of files (two files for each of the mapped parameters, plus two files for each parameter's uncertainty grid) compressed in zip format.

The files extensions are:
.hdr = An ASCII file specifying the geometry of the grid
.fit = A raster file containing the gridded data

These files are intended for use with any GIS software that can import ESRI raster data. The file names are "parameter.extension" and "parameter_std.extension", where "parameter" can be any of "pga", "pgv", "psa03", "psa10", "psa30", or "mi" (for Peak Ground Acceleration, Peak Ground Velocity, pseudo-spectral acceleration at 0.3, 1.0, and 3.0 seconds, and macroseismic intensity, respectively). The units of acceleration are percent-g, and velocity is cm/s. The _std files contain the uncertainties in natural log units, except for intensity which is linear.

raster.zip is available for all events, but the spectral acceleration values are typically only included for earthquakes of magnitude 5.0 and larger.

Lists of input data

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.

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.

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.

The Modified Mercalli Intensity Scale

English

Intensity	Shaking	Description/Damage
I	Not felt	Not felt except by a very few under especially favorable conditions.
II	Weak	Felt only by a few persons at rest,especially on upper floors of buildings.
III	Weak	Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated.
IV	Light	Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably.
V	Moderate	Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop.
VI	Strong	Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.
VII	Very strong	Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.
VIII	Severe	Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.
IX	Violent	Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations.
X	Extreme	Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent.

Bahasa Malaysia

Intensiti	Keterangan
I	Gegaran tidak dirasai.
II	Gegaran dirasakan oleh beberapa orang sahaja yang berada dalam keadaan pegun terutama di tingkat atas bangunan tinggi. Objek-objek ringan yang bergantungan akan bergoyang atau berayun.
III	Gegaran dirasai nyata di dalam rumah atau bangunan tetapi tidak disedari sebagai getaran gempa bumi. Getaran seperti seolah-olah sebuah trak ringan bergerak dan jangka masa getaran boleh dianggarkan.
IV	Gegaran dirasakan oleh ramai orang pada waktu siang dan malam, gegaran boleh menyebabkan beberapa orang terbangun. Tingkap, pinggan mangkuk, pintu bergetar dan kaca berdenting. Dinding kayu dan rangka bangunan berbunyi. Getaran seperti seolah-olah sebuah trak berat menghentam dinding.
V	Gegaran dirasakan oleh hampir semua penduduk. Orang yang tidur terjaga. Objek-objek yang tidak stabil berubah tempat. Pintu berayun, terbuka dan tertutup. Bidai, bingkai gambar dan pokok bergoyang.
VI	Gegaran dirasakan oleh semua penduduk. Kebanyakan orang terkejut dan berlari ke luar bangunan. Berjalan dalam keadaan tidak stabil. Perabut bergerak dan berubah tempat, siling dan dinding retak. Kerosakan ringan berlaku.
VII	Semua orang keluar dari rumah. Kerosakan ringan pada rumah dan bangunan yang dibina dengan struktur yang baik tetapi pada bangunan dengan struktur yang kurang baik terjadi keretakan. Dirasai oleh orang yang menaiki kenderaan.
VIII	Kerosakan ringan pada bangunan yang mempunyai struktur yang kuat. Keretakan pada bangunan yang mempunyai struktur kurang baik. Dinding panel yang terkeluar dari struktur rangka. Serombong dan monumen-monumen roboh. Air perigi atau kolam menjadi keruh. Orang yang menaiki kenderaan terganggu.
IX	Kerosakan pada bangunan yang berstruktur kuat, rangka-rangka rumah menjadi tidak lurus dan banyak yang retak. Bangunan dan rumah berganjak dari lokasinya. Paip-paip bawah tanah pecah.
X	Kerosakan pada bangunan yang berstruktur kayu, rangka bangunan dan rumah musnah, terjadi rekahan dalam tanah, rel-rel di landasan rosak, tanah runtuh di kawasan yang curam dan berdekatan sungai.

References

USGS Modified Mercalli Intensity Scale