Metadata:
Identification_Information:
Citation:
Citation_Information:
Originator: US Geological Survey and the U.S. Geological Survey
Publication_Date: 1994-08-20
Publication_Time: 10:45:45 UTC
Title:
Advanced National Seismic System (ANSS), ShakeMap,
Global Region, Maps of ground shaking
and intensity for event nm604083,
ARKANSAS
Edition: Map Version 1; Code Version 3.5
Geospatial_Data_Presentation_Form: Map
Online_Linkage: http://earthquake.usgs.gov/eqcenter/shakemap
Description:
Abstract:
ShakeMap is designed as a rapid response tool to portray the
extent and variation of ground shaking throughout the affected
region immediately following significant earthquakes. Ground
motion and intensity maps are derived from peak ground motion
amplitudes recorded on seismic sensors (accelerometers), with
interpolation based on both estimated amplitudes where data are
lacking, and site amplification corrections. Color-coded
instrumental intensity maps are derived from empirical relations
between peak ground motions and Modified Mercalli intensity.
This ShakeMap describes the event: nm604083,
ARKANSAS
Purpose:
As a rapid response tool, the ShakeMap ground motion values are
used for emergency response, loss estimation, assessment of damage
to the lifeline and utility networks, and for providing information
to the general public.
Time_Period_of_Content:
Currentness_Reference: ground condition
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 1994-08-20
Time_of_Day: 10:45:45 UTC
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -92.31300000000000
East_Bounding_Coordinate: -89.81300000000000
North_Bounding_Coordinate: 37.15000000000000
South_Bounding_Coordinate: 35.13000000000000
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: ShakeMap
Theme_Keyword: peak ground motions
Theme_Keyword: shaking intensity
Theme_Keyword: instrumental intensity
Theme_Keyword: earthquake damage
Theme_Keyword: Advanced National Seismic Systems (ANSS)
Theme_Keyword: US Geological Survey
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Global
Access_Constraints: none
Use_Constraints: none
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: ShakeMap Working Group
Contact_Person: David J. Wald
Contact_Position: Geophysicist
Contact_Address:
Address_Type: mailing
Address:
N/A
City: N/A
State_or_Province: N/A
Postal_Code: N/A
Country: USA
Contact_Voice_Telephone: N/A
Contact_Facsimile_Telephone: N/A
Contact_Electronic_Mail_Address: N/A
Browse_Graphic:
Browse_Graphic_File_Name:
http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/nm604083/intensity.html
Browse_Graphic_File_Description:
Instrumental Intensity ShakeMap within a web page; all other ShakeMap
maps and products can be accessed from this site. Typically
the image itself is 600x400 pixels and about 100k bytes in size.
Browse_Graphic_File_Type: JPEG
Cross_Reference:
Citation_Information:
Originator: Wald, D.J.
Originator: Quitoriano, V.
Originator: Heaton, T.H.
Originator: Kanamori, H.
Originator: Scrivner, C.W.
Originator: Worden, C.B.
Title:
TriNet "ShakeMaps": rapid generation of instrumental
ground motion and intensity maps for earthquakes in
Southern California
Publication_Date: 1999
Series_Information:
Series_Name: Earthquake Spectra
Issue_Identification: Vol. 15, No. 3
Other_Citation_Details: pp 537-556
Online_Linkage: http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/about.html#references
Cross_Reference:
Citation_Information:
Originator: Wald, D.J.
Originator: Quitoriano, V.
Originator: Heaton, T.H.
Originator: Kanamori, H.
Title:
Relationship between Peak Ground Acceleration, Peak Ground Velocity, and Modified Mercalli Intensity for Earthquakes in California
Publication_Date: 1999
Series_Information:
Series_Name: Earthquake Spectra
Issue_Identification: Vol. 15, No. 3
Other_Citation_Details: pp 557-564
Online_Linkage: http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/about.html#references
Cross_Reference:
Citation_Information:
Originator: Wald, D.J.
Originator: Worden, C.B.
Originator: Quitoriano, V.
Originator: Pankow, K.
Title: ShakeMap Manual: Users Guide, Technical Manual, and Software Guide, USGS Techniques and Methods 12-A1
Publication_Date: 2005
Series_Information:
Series_Name: U.S. Geological Survey [Open File Report]
Issue_Identification: [ZZZ-03]
Other_Citation_Details: [128 pp]
Online_Linkage: http://pubs.usgs.gov/tm/2005/12A01/
Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
Slight variations in peak ground motions and spectral values
may depend on processing. Corrections or changes in station
and amplitude information are reflected by the authoritative
seismic network. In addition, changes in magnitude may result
in changes to estimated ground motions in areas with sparse
seismic station coverage.
Completeness_Report:
Included in this version are data available up to the time processed.
Additional data (seismic stations) may be added at a later time.
Logical_Consistency_Report:
Ground motion data are direct measurements only at the location
of seismic stations; all other data are interpolated (as
described in the citations). Seismic station coverage varies
in density as well as instrumentation across the region in
question. Uncertainty in the reported ground motions generally
increases with distance from seismic stations, and in areas of
very low station density may be largely the product of empirical
relationships. Uncertainties in ground motions may also arise
from inaccurate ground motion amplitudes from seismic stations,
or inaccurate information regarding earthquake epicenter or
magnitude, as reported by the generating network.
Lineage:
Process_Step:
Process_Description:
Shaking maps are prepared by contouring shaking information
interpolated onto a square grid uniformly sampled at a
spacing of 1 minute (about 1.6 km) throughout California. If
there were stations at each of the tens of thousands of grid
points, then the creation of shaking maps would be relatively
simple. Of course stations are not available for all of these
grid points, and in many cases grid points may be tens of
kilometers from the nearest reporting station. The overall
mapping philosophy is to combine information from individual
stations, geology (representing site amplification), and the
distance to the epicenter or causative fault to create the
best composite map. The procedure produces reasonable estimates
at grid points located far from available data, while
preserving the detailed shaking information available for
regions where there are stations nearby.
Estimation of shaking over the regional extent for an earthquake
in California is obtained by the spatial interpolation of the
measured ground motions with geologically based frequency and
amplitude-dependent site corrections. We use the California
Site Condition Map (California Geological Survey, CGS) maps
of National Earthquake Hazard Reduction Program (NEHRP)
classification site conditions as the basis for our site
corrections. These site condition maps have coverage throughout
the state at 1:250,000 scale (Wills et al., 2000). We use the
amplification factors of Borcherdt et al. (1994). In addition,
ShakeMap ground motions in regions of sparse station spacing
are estimated using ground motion regression, initially from
a point location at the epicenter. Later, as information about
fault dimensions became available (in the form of aftershocks,
source rupture models, and observed surface slip), the fault
location and rupture dimensions are used as the basis for
ground motion estimation.
First, peak ground motion parameters are recovered for each
station and associated with a particular earthquake origin time
and epicenter. We then create a coarse, uniformly spaced grid
of 30-km spaced "phantom" stations. Peak ground motions and
spectral acceleration values are assigned to each coarse grid
point using a ground motion attenuation relationship for
rock sites given the magnitude of the earthquake and distance
to each grid point. In practice, we apply a static correction
to the amplitudes of the regression by using the network-determined
magnitude, predicting the observed amplitudes, and correcting for
an amplitude bias term between the predictions and the data.
Site corrections are then used to interpolate from ground
motions recorded on a fairly sparse, non-uniformly spaced
network of stations to maps showing spatially continuous
functions (i.e., contours). Prior to interpolation, we reduce
the ground motion amplitudes to a common reference, in this
case bedrock motions. Peak ground motion amplitudes from the
seismic stations are corrected to rock site conditions; and
the observations (corrected to rock) and the coarse phantom
stations (computed for rock) are then interpolated to a fine
rock site grid (roughly 1.6-km spacing). We scale the peak
acceleration (PGA) amplitude with the Borcherdt et al. (1994)
short-period amplification factors while the peak ground
velocity (PGV) values are corrected with the mid-period
factors. Response spectral values are scaled by the short-period
factors at 0.3 sec, and by the mid-period response at 1.0 and
3.0 seconds. The site correction procedure is applied so that
the original data values are returned at each station; hence,
the actual recorded motions are preserved in the process and
the final contours reflect the observations wherever they exist.
Next, the interpolated rock grid is corrected at each point
for local site amplification and instrumental intensity map is
generated by relating the peak ground acceleration or velocity
at each grid point to intensity as described by Wald et al. (1999).
This fine grid is saved and exported to the file "grid.xyz". A
continuous surface is also fit to the fine grid to produce
the contour maps and GIS formatted maps.
Process_Date: 1994-08-20
Process_Time: 10:45:45 UTC
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Geographic:
Latitude_Resolution: 0.01669421487603
Longitude_Resolution: 0.01666666666667
Geographic_Coordinate_Units: Decimal degrees
Geodetic_Model:
Horizontal_Datum_Name: World Geodetic System 1984
Ellipsoid_Name: WGS 84
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257
Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
File grid.xyz
Values of the peak amplitudes at the ShakeMap map grid nodes.
File is ASCII text in the following format:
First line is a header, space-delimited, with all of the following:
><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.
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>
>pga = peak ground motion (acceleration, as percent of g)
>pgv = peak ground motion (velocity in cm/s)
>mmi = estimated instrumental intensity
>psa03 = spectral acceleration at 0.3 s period, 5% damping (percent of g)
>psa10 = spectral acceleration at 1.0 s period, 5% damping (percent of g)
>psa30 = spectral acceleration at 3.0 s period, 5% damping (percent of g)
Entity_and_Attribute_Detail_Citation:
http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/nm604083/about_formats.html#xyz
Overview_Description:
Entity_and_Attribute_Overview:
File grid.xml
Specifies the earthquake and ShakeMap parameters, and values
of the peak amplitudes at the ShakeMap map grid nodes. File is XML
text.
Entity_and_Attribute_Detail_Citation:
http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/nm604083/about_formats.html#xml
Detailed_Description:
Entity_Type:
Entity_Type_Label: mi.dbf (shapefile from "shape.zip" download file)
Entity_Type_Definition: Polygons of estimated instrumental intensity
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition: Estimated instrumental intensity (double)
Attribute_Definition_Source:
Wald, et al., Relationship between Peak Ground Acceleration, Peak
Ground Velocity, and Modified Mercalli Intensity for Earthquakes
in California, Earthquake Spectra, Vol. 15, No. 3, 1999, pp 557-564.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 10.0
Attribute_Units_of_Measure: Intensity
Attribute_Measurement_Resolution: 0.1
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Estimated instrumental intensity (double)
Attribute_Definition_Source:
Wald, et al., Relationship between Peak Ground Acceleration, Peak
Ground Velocity, and Modified Mercalli Intensity for Earthquakes
in California, Earthquake Spectra, Vol. 15, No. 3, 1999, pp 557-564.
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 10.0
Attribute_Units_of_Measure: Intensity
Attribute_Measurement_Resolution: 0.1
Detailed_Description:
Entity_Type:
Entity_Type_Label: pga.dbf (shapefile from "shape.zip" download file)
Entity_Type_Definition: Polygons of peak ground motion (acceleration)
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition: Peak ground motion (acceleration, as integer percent of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -200.0
Range_Domain_Maximum: 200.0
Attribute_Units_of_Measure: percent of g
Attribute_Measurement_Resolution: 4
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Peak ground motion (acceleration, as fraction of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -200.0
Range_Domain_Maximum: 200.0
Attribute_Units_of_Measure: fraction of g
Attribute_Measurement_Resolution: 0.04
Detailed_Description:
Entity_Type:
Entity_Type_Label: pgv.dbf (shapefile from "shape.zip" download file)
Entity_Type_Definition: Polygons of peak ground motion (velocity)
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition: Peak ground motion (velocity in cm/s, integer)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -500.0
Range_Domain_Maximum: 500.0
Attribute_Units_of_Measure: cm/s
Attribute_Measurement_Resolution: 4
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Peak ground motion (velocity in cm/s, double)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -500.0
Range_Domain_Maximum: 500.0
Attribute_Units_of_Measure: cm/s
Attribute_Measurement_Resolution: 4
Detailed_Description:
Entity_Type:
Entity_Type_Label: psa03.dbf (shapefile (from "shape.zip" download file)
Entity_Type_Definition: Polygons of spectral acceleration at 0.3 s period, 5% damping
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition:
Spectral acceleration at 0.3 s period, 5% damping (integer percent of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: percent of g
Attribute_Measurement_Resolution: 4
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Spectral acceleration at 0.3 s period, 5% damping (fraction of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: fraction of g
Attribute_Measurement_Resolution: 0.04
Detailed_Description:
Entity_Type:
Entity_Type_Label: psa10.dbf (shapefile from "shape.zip" download file)
Entity_Type_Definition: Polygons of spectral acceleration at 1.0 s period, 5% damping
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition:
Spectral acceleration at 1.0 s period, 5% damping (integer percent of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: percent of g
Attribute_Measurement_Resolution: 4
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Spectral acceleration at 1.0 s period, 5% damping (fraction of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: fraction of g
Attribute_Measurement_Resolution: 0.04
Detailed_Description:
Entity_Type:
Entity_Type_Label: psa30.dbf (shapefile from "shape.zip" download file)
Entity_Type_Definition: Polygons of spectral acceleration at 3.0 s period, 5% damping
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition:
Spectral acceleration at 3.0 s period, 5% damping (integer percent of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: 2
Range_Domain_Maximum: 34
Attribute_Units_of_Measure: percent of g
Attribute_Measurement_Resolution: 4
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Spectral acceleration at 3.0 s period, 5% damping (fraction of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: fraction of g
Attribute_Measurement_Resolution: 0.04
Detailed_Description:
Entity_Type:
Entity_Type_Label: pga.dbf (shapefile from "hazus.zip" download file)
Entity_Type_Definition: Polygons of "mean" ground motion (acceleration), scaled from recorded peak
values by 15% (empirical correction from peak to mean) to conform to HAZUS input requirements.
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition: Mean ground motion (acceleration, as integer percent of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -200.0
Range_Domain_Maximum: 200.0
Attribute_Units_of_Measure: percent of g
Attribute_Measurement_Resolution: 4
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Mean ground motion (acceleration, as fraction of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -200.0
Range_Domain_Maximum: 200.0
Attribute_Units_of_Measure: fraction of g
Attribute_Measurement_Resolution: 0.04
Detailed_Description:
Entity_Type:
Entity_Type_Label: pgv.dbf (shapefile (from "hazus.zip" download file)
Entity_Type_Definition: Polygons of "mean" ground motion (velocity), scaled from recorded peak
values by 15% (empirical correction from peak to mean) to conform to HAZUS input requirements.
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition: Mean ground motion (velocity in inches/sec, integer)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -200.0
Range_Domain_Maximum: 200.0
Attribute_Units_of_Measure: cm/s
Attribute_Measurement_Resolution: 2
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Mean ground motion (velocity in inches/s, double)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -500.0
Range_Domain_Maximum: 500.0
Attribute_Units_of_Measure: cm/s
Attribute_Measurement_Resolution: 2.0
Detailed_Description:
Entity_Type:
Entity_Type_Label: psa03.dbf (shapefile from "hazus.zip" download file)
Entity_Type_Definition: Polygons of "mean" spectral acceleration at 0.3 s period, 5% damping, scaled from
recorded peak values by 15% (empirical correction from peak to mean) to conform to HAZUS input
requirements.
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition:
Mean Spectral acceleration at 0.3 s period, 5% damping (integer percent of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: percent of g
Attribute_Measurement_Resolution: 4
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Mean spectral acceleration at 0.3 s period, 5% damping (fraction of g), scaled
from recorded peak values by 15% (empirical correction from peak to mean) to conform to HAZUS input
requirements.
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: fraction of g
Attribute_Measurement_Resolution: 0.04
Detailed_Description:
Entity_Type:
Entity_Type_Label: psa10.dbf (shapefile from "hazus.zip" download file)
Entity_Type_Definition: Polygons of mean spectral acceleration at 1.0 s period, 5% damping, scaled from
recorded peak values by 15% (empirical correction from peak to mean) to conform to HAZUS input
requirements.
Entity_Type_Definition_Source: ESRI Shapefile Technical Description
Attribute:
Attribute_Label: GRID_CODE
Attribute_Definition:
Mean spectral acceleration at 1.0 s period, 5% damping (integer percent of g)
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: percent of g
Attribute_Measurement_Resolution: 4
Attribute:
Attribute_Label: VALUE
Attribute_Definition: Mean spectral acceleration at 1.0 s period, 5% damping (fraction of g), scaled from
recorded peak values by 15% (empirical correction from peak to mean) to conform to HAZUS input
requirements.
Attribute_Definition_Source: self-evident
Attribute_Domain_Values:
Range_Domain:
Range_Domain_Minimum: -400.0
Range_Domain_Maximum: 400.0
Attribute_Units_of_Measure: fraction of g
Attribute_Measurement_Resolution: 0.04
Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: United States Geological Survey, Advanced National Seismic System (ANSS)
Contact_Person: David J Wald
Contact_Position: Geophysicist
Contact_Address:
Address_Type: mailing address
Address: P.O. Box 25046
City: Lakewood
State_or_Province: CO
Postal_Code: 80225
Country: USA
Contact_Voice_Telephone: 303-273-8441
Contact_Facsimile_Telephone: (303) 273-8600
Contact_Electronic_Mail_Address: wald@usgs.gov
Resource_Description: Shakemap data for nm604083
Distribution_Liability:
Some USGS information accessed through this page may be preliminary in
nature and presented prior to final review and approval by the
Director of the USGS. This information is provided with the
understanding that it is not guaranteed to be correct or complete, and
conclusions drawn from such information are the sole responsibility of
the user.
These are automatic computer generated maps and have not necessarily
been checked by human oversight, so they may contain errors. Further,
the input data is raw and unchecked, and may contain errors.
Contours can be misleading since data gaps may exist. Caution should
be used in deciding which features in the contour patterns are
required by the data. Ground motions and intensities can vary greatly
over small distances, so these maps are only approximate; when maps
are enlarged beyond the limits of the original data in an effort to
show small areas, the maps are unreliable.
These maps are preliminary in nature and will be updated as data
arrives from distributed sources.
The estimated intensity map is derived from ground motions recorded by
seismographs and represents Modified Mercalli Intensities (MMI's) that
are likely to have been associated with the ground motions. Unlike
conventional Modified Mercalli Intensities, the estimated intensities
are not based on observations of the earthquake effects on people or
structures.
Locations within the same intensity area will not necessarily
experience the same level of damage since damage depends heavily on
the type of structure, the nature of the construction, and the details
of the ground motion at that site. For this reason more or less damage
than described in the MMI scale may occur.
Large earthquakes can generate very long-period ground motions that
can cause damage at great distances from the epicenter; although the
intensity estimated from the ground motions may be small, significant
effects to large structures (bridges, tall buildings, storage tanks)
may be notable.
The ground motion levels and descriptions associated with each
intensity value are based on recent damaging earthquakes. There may be
revisions in these parameters as more data become available or from
further improvements in methodology.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: ESRI shapefile
Format_Information_Content:
Ground shaking intensity, acceleration, and velocity contours
File_Decompression_Technique: unzip
Transfer_Size: 2 megabytes
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/nm604083/download/shape.zip
Network_Resource_Name:
http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/nm604083/download/hazus.zip
Digital_Form:
Digital_Transfer_Information:
Format_Name: Text
Format_Version_Number: 1.0
Format_Specification:
Within lines, values are delimited by spaces.
First line is a header containing <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 remaining lines contain <lon> <lat> <pga> <pgv> <mmi>
<psa03> <psa10> <psa30>
Format_Information_Content: Ground-shaking intensity and acceleration data
File_Decompression_Technique: unzip
Transfer_Size: 0.5 megabytes
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/nm604083/download/grid.xyz.zip
Fees: none
Metadata_Reference_Information:
Metadata_Date: 1994-08-20
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U.S. Geological Survey, GEO-CR-GHT
Contact_Person: David J. Wald
Contact_Position: Geophysicist
Contact_Address:
Address_Type: mailing
Address:
U.S. Geological Survey
P.O. Box 25046, Mail Stop 966
City: Denver
State_or_Province: CO
Postal_Code: 80225-0046
Country: USA
Contact_Voice_Telephone: (303) 273-8441
Contact_Facsimile_Telephone: (303) 273-8600
Contact_Electronic_Mail_Address: wald@usgs.gov
Metadata_Standard_Name: Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998