Guralp Systems ART User Manual
ART 3.0
Seismic Analysis and Research
Tool
User guide
Part No. MAN-SWA-0003
Designed and manufactured by
Güralp Systems Limited
3 Midas House, Calleva Park
Aldermaston RG7 8EA
England
Proprietary Notice: The information in this
manual is proprietary to Güralp Systems Limited
and may not be copied or distributed outside the
approved recipient's organisation without the
approval of Güralp Systems Limited. Güralp
Systems Limited shall not be liable for technical
or editorial errors or omissions made herein, nor
for incidental or consequential damages resulting
from the furnishing, performance, or usage of this
material.
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Table of Contents
1 Introduction...........................................................................4
2 Getting Started.......................................................................7
2.1 Installing ART.....................................................................................7
2.2 Setting up sensor information............................................................7
2.2.1 Examples......................................................................10
2.3 Starting ART.....................................................................................11
2.3.1 Start from the ART icon................................................11
2.3.2 Starting from SCREAM..................................................11
3 Using ART.............................................................................13
3.1 Importing data from Scream!...........................................................13
3.2 The main ART window......................................................................13
3.2.1 Import data .................................................................14
3.2.2 Options.........................................................................15
3.2.3 Interactive selection of filter parameters.....................19
3.2.4 Add/edit metadata.......................................................20
3.2.5 Filter time-histories......................................................23
3.2.6 Export data...................................................................23
3.2.7 Clear time-histories......................................................26
3.2.8 Event Manager.............................................................27
3.2.9 ‘Unfiltered?’ check box.................................................27
3.2.10 Central list box.............................................................27
3.2.11 Strong-motion parameters...........................................28
3.2.12 View time-histories.......................................................34
3.2.13 View time-histories on map..........................................36
3.2.14 Particle motions...........................................................37
3.2.15 Husid (Arias intensity) plot...........................................39
3.2.16 Energy density plot......................................................40
3.2.17 Fourier amplitude spectrum.........................................42
3.2.18 Elastic response spectra..............................................45
3.2.19 Elastic input energy spectra.........................................47
3.2.20 Drift spectra.................................................................49
3.2.21 Comparisons................................................................50
4 References...........................................................................54
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5 Software Change History.......................................................60
5.1 Changes from ART 2.........................................................................60
5.2 Changes from ART 1.........................................................................61
6 Revision history....................................................................63
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1 Introduction
ART 3.0, Güralp Systems' Strong-Motion Analysis and Research
Tool is a windows program which allows users of seismometers
(accelerometers or velocimeters) produced by Güralp Systems
Ltd, to process and analyze their recorded data for engineering
seismology and earthquake engineering purposes. The timehistories can be exported in a number of different strongmotion record formats that are currently in use today.
ART3.0 is a major update of the second version of ART
(ART2.0), which was released in 2006. A number of
improvements were made following requests received from
users, which are listed in section 5.1, page 60.
ART 3.0 is supplied in the standard distribution of Scream!
versions 4.5 and later. It is also compatible with older versions
of Scream!.
ART works closely with Scream! to make analysing seismic data
easy. Scream!'s visualization and filtering capabilities allow you
to view time series and quickly identify events. Strong-motion
records can then be directly imported into ART from Scream!
by selecting the appropriate portion of the record in Scream! this will automatically start ART. Previously recorded data in
Güralp Compressed Format (GCF) can be read in from prerecorded files and analyzed. In addition, data can be imported
into ART via a modem.
Currently the following functions, which are important for
engineering seismologists and earthquake engineers, are
supported (in addition most of these functions allow selection
of multiple time-histories so a comparison between records is
possible).
• plotting uncorrected acceleration, velocity and
displacement against relative or absolute time;
• automatic correcting of recorded time-history for
instrument response to obtain ground acceleration;
• filtering of acceleration time-history using user-defined
filters;
• plotting corrected acceleration, velocity and
displacement against relative or absolute time;
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• calculation and plotting of Fourier amplitude spectra of
time-histories and of pre-event portions of records
including the signal-to-noise ratios;
• calculation and plotting of Arias intensities against time;
• calculation and plotting of energy densities against time;
• calculation and plotting, both on standard and tripartite
graphs, of linear elastic response spectra;
• calculation and plotting of linear elastic absolute and
relative input energy spectra;
• calculation and plotting of drift spectra for a cantilever
shear-beam for different material types;
• calculation of peak ground acceleration (PGA), peak
ground velocity (PGV) and peak ground displacement
(PGD);
• calculation of PGV/PGA;
• calculation of A95 parameter;
• calculation of sustained maximum acceleration and
velocity;
• calculation of JMA instrumental intensities;
• calculation of response spectrum intensities using user-
defined limits;
• calculation of acceleration spectrum intensities using
user-defined limits;
• calculation of RMS acceleration, velocity and
displacement;
• calculation of cumulative absolute velocities using user-
defined minimum acceleration thresholds;
• calculation of absolute and relative bracketed, significant
and uniform strong-motion durations using user-defined
limits;
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• calculation of number of absolute and effective cycles of
acceleration using peak counting - including or excluding
non-zero crossings and rainflow counting techniques;
• calculation of mean, predominant spectral, smoothed
spectral predominant and average spectral periods;
• plotting particle motions both in two and three
dimensions;
• basic database functionality to allow earthquake and
station metadata to be added, used and exported;
• comparison of observed elastic response spectra to
predicted spectra from various ground-motion prediction
equations and seismic design codes;
• plotting of acceleration, velocity and displacement time-
histories on map;
• exporting the uncorrected and corrected spectra in these
commonly used strong-motion record formats:
• Columns;
• CSMIP as used by the California Strong-Motion
Instrumentation Program;
• ISESD as used by the Internet Site for European
Strong-Motion Data;
• K-Net as used by Kyoshin Net;
• PEER as used by Pacific Earthquake Engineering
Research Center;
• SMC as used by the US Geological Survey;
• SAC as used by Seismic Analysis Code;
• Microsoft Excel .xls;
• Matlab .mat.
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2 Getting Started
The material in this chapter covers the installation,
configuration and invocation of ART 3.0.
2.1 Installing ART
ART is included in the standard Scream! distribution for
Windows, which is available for free download.
ART uses the Matlab runtime library for its mathematical
routines. This is supplied as part of the installer and may be
freely distributed.
To download Scream!, send an e-mail to scream@guralp.com,
including information about your institution and the type(s) of
equipment you are using.
To install the package, double-click on its icon and follow the
instructions in the installer. Choose the Typical installation
option to ensure that ART and its supporting libraries are all
installed.
2.2 Setting up sensor information
Before it can analyse data from your instruments, ART needs to
know detailed calibration information for each one.
Note:
If you start ART from within Scream! (as in section 2.3.2
on page 11) without setting up the relevant sensor information,
you will receive an error message saying:
A VPC= entry for {SYSTEM_ID-SERIAL} was not found in
calvals.txt
and you should follow the procedure in this section before retrying.
The calibration information must be provided in a file called
calvals.txt, which should be kept in the ART/Scream!
program directory. You can create and edit this file from inside
Scream! by right-clicking on the digitizer's icon in the main
window and selecting Calvals....
The file is divided into sections, each beginning with a title in
square brackets. The title gives the System ID and serial
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number (as given by the first four characters of the Stream ID)
for the digitizer which produces the data stream.
For example: to add calibration information for a digitizer with
System ID GURALP outputting streams DEMOZ2, DEMON2,
DEMOE2, etc., you would add a section beginning with the line
[GURALP-DEMO]
If you move an instrument from one digitizer to another, you
will need to update the calvals.txt file to reflect the change.
• To set the serial number of the instrument, include the
line
Serial-Nos=serial-number
• Scream! cannot tell what instrument is connected to the
digitizer. This line is provided to help you remember
which set of calibration values you have used, and to
provide a title for calibration graphs. If you attach a
different instrument to the same digitizer, you will need
to enter new calibration values to reflect the new
instrument.
• To set the sensitivity of the digitizer, include the line
VPC=sensitivity
VPC stands for voltage per count, measured in units of
μV/count. This is sometimes given as μV/Bit on the digitizer
calibration sheet.
• To set the sensitivity of the calibration channel, include
the line
CALVPC=sensitivity
as for the other digitizer channels.
• To set the value of the calibration resistor, include the
line
CALRES=resistance
Güralp Systems digitizers normally use a 51 kΩ resistor
(CALRES=51000).
• To set the sensor type, include the line
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TYPE=model-number
e.g. 3T, 5T, etc..
• To set the response of the sensor, include the line
RESPONSE=response-type unit
The values you can use are given in the table below.
Sensor
Sensor type code
(response-type)
Units
(V/A)
CMG-5T or 5TD,
DC – 100 Hz response
CMG-5_100HZ
A
CMG-40T-1 or 6T-1,
1 s – 100 Hz response
CMG-40_1S_100HZ
V
CMG-40T-1 or 6T-1,
2 s – 100 Hz response
CMG-40_2S_100HZ
V
CMG-40T-1 or 6T-1,
10 s – 100 Hz response
CMG-40_10S_100HZ
V
CMG-40, 20 s – 50 Hz response
CMG-40_20S_50HZ
V
CMG-40, 30 s – 50 Hz response
CMG-40_30S_50HZ
V
CMG-3T or 3ESP,
30 s – 50 Hz response
CMG-3_30S_50HZ
V
CMG-40, 60 s – 50 Hz response
CMG-40_60S_50HZ
V
CMG-3T or 3ESP,
60 s – 50 Hz response
CMG-3_60S_50HZ
V
CMG-3T or 3ESP,
100 s – 50 Hz response
CMG-3_100S_50HZ
V
CMG-3T or 3ESP,
120 s – 50 Hz response
CMG-3_120S_50HZ
V
CMG-3T, 360 s – 50 Hz response
CMG-3_360S_50HZ
V
CMG-3TB or 3V / 3ESP borehole,
30 s – 50 Hz response
CMG-3B_30S_50HZ
V
CMG-3TB or 3V / 3ESP borehole,
100 s – 50 Hz response
CMG-3B_100S_50HZ
V
CMG-3TB or 3V / 3ESP borehole,
120 s – 50 Hz response
CMG-3B_120S_50HZ
V
CMG-3TB or 3V / 3ESP borehole,
360 s – 50 Hz response
CMG-3B_360S_50HZ
V
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Sensor
Sensor type code
(response-type)
Units
(V/A)
CMG-3TB or 3V / 3ESP borehole,
360 s – 50 Hz response
CMG-3B_360S_100HZ
V
Some English descriptions are also accepted, e.g.
“120s velocity”, “100Hz acceleration”.
• To set the sensitivities (or gains) of the sensor
components, include the line
G=vertical-sens,N/S-sens,E/W-sens
These values are given on the sensor calibration sheet. For
velocity sensors, they are given in units of V m–1 s (V/m/s).
The gain of an accelerometer is expressed in V m-1 s2 (V/m/
s2). Because Güralp Systems sensors and digitizers use
differential inputs and outputs, the sensitivity is quoted as
2 × (single-ended sensitivity) on the calibration sheet.
• To set the coil constants of the sensor components,
include the line
COILCONST=ZCC,NCC,ECC
Where ZCC is the vertical coil constant, NCC is the
North/South coil constant and ECC is the East/West cost
constant. These values are given on the sensor calibration
sheet.
• To set the local acceleration due to gravity, include the
line
GRAVITY=acceleration
You should give this value in m s–2, if you know it. If you
miss out this line, Scream! will use a standard average
g value of 9.80665 m s–2.
2.2.1 Examples
The calibration information for a CMG-3T weak-motion velocity
sensor might look like the following:
[GURALP-CMG3]
Serial-Nos=T3X99
VPC=3.153,3.147,3.159
G=1010,1007,1002
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COILCONST=0.02575,0.01778,0.01774
CALVPC=3.161
CALRES=51000
TYPE=CMG-3T
RESPONSE=CMG-3_30S_50HZ V
GRAVITY=9.80122
CMG-5TD accelerometers use 1 Ω calibration resistors, and
their coil constant is set to unity. Older CMG-5TD instruments,
based on Mk2 digitizer hardware, do not have calibration input
facilities, and thus the CALVPC entry is omitted. For example:
[GURALP-CMG5]
Serial-Nos=T5585
VPC=2.013,2.028,2.036
G=0.256,0.255,0.255
COILCONST=1,1,1
CALRES=1
TYPE=CMG-5T
RESPONSE=CMG-5_100HZ A
GRAVITY=9.81089
2.3 Starting ART
ART can be started in two ways, either from SCREAM or by
double clicking on the ART icon.
2.3.1 Start from the ART icon
Double-clicking on the ART icon will start the application and
cause the main ART window to open.
Clicking on the ‘Import data’ button at the top of the left-hand
column of the main ART window opens up a file selection
window from which a GCF time-history can be selected to
import and analyze.
2.3.2 Starting from SCREAM
Within Scream!, open a WaveView window displaying the event
you are interested in. Click on the Pause icon to stop the
traces moving then, using the mouse, select the parts of the
time-histories that you want to analyze while holding down
either the Ctrl or Shift keys.
If you use the Ctrl key, the
first
and
last
streams in the selected
area will be analyzed. This is useful for picking two streams
from many for comparison. If you use the Shift key, a
contiguous set of streams are selected.
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When the Ctrl or Shift key is released, a pop-up menu will
appear (after a short delay) asking which add-on program you
want to run. Select ART and the main ART window will open
with the selected time-histories automatically loaded.
The picture below shows a Scream! WaveView window with two
streams selected (using the Shift key).
The second illustration shows the selection of two non-adjacent
streams for comparison, using the Ctrl key
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3 Using ART
The following sections discuss the features currently
implemented in ART and how to use them.
When a time-history is loaded into ART, either via SCREAM, via
the Import Data button (see below) or via the Event Manager, a
correction for instrument response and, if required, a
conversion to acceleration is automatically performed. Lowpass filtering with a transition band given in ‘Options’ window
(see below) is also undertaken, The algorithm used to remove
the instrument response is the same as that used in BAP v1.0
(Converse & Brady, 1992) but the transfer function used to
correct the time-history is derived from the poles and zeros of
the originating instrument (e.g. a CMG-5T).
3.1 Importing data from Scream!
The most common and convenient way to get data into ART is
to import it directly from a WaveView window within Scream!.
This is fully described in section 2.3.2 on page 11. It is also
straightforward to import GCF files without running scream.
This is described in section 3.2.1 on page 14.
3.2 The main ART window
The main ART window has:
• two columns of buttons (PROCESS and VIEW) for
analyzing and processing the selected time-histories;
• a list box in the middle for choosing which time-history is
being processed and analyzed; and
• a text box at the bottom for displaying the metadata on
the earthquake and station associated with the selected
time-history (this information is only displayed if a single
time-history is selected).
The full window is shown overleaf.
The following sections discuss the available functions starting
with the left-hand column of buttons (PROCESS).
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3.2.1 Import data
Clicking on the ‘Import data’ button at the top of the left-hand
column opens up a file selection window from which the GCF
time-history to import can be selected (see below).
Many time-histories can be loaded into ART using this file
selection window and, in addition, the window can be opened
as many times as required to load in all the data required.
Once the required time-histories have been located, double
clicking on the filenames (multiple records can be selected by
holding down the Shift or Ctrl keys) or clicking on the filenames
and clicking ‘Add’ will add them to the list of files to import (in
the right-hand list box). To import the data listed in the right-
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hand list box) click on ‘Done’ and their names will be added to
the list given in the central box. As stated above, the data is
automatically corrected for instrument response and converted
to acceleration, if required.
3.2.2 Options
Clicking on the ‘Options’ button opens a window (see below)
displaying the options that are currently used for display of
acceleration, velocity and displacement parameters,
appearance of some windows, filtering and for the calculation
of the strong-motion parameters. The parameters given in this
window can be altered either by clicking in the white box next
to the name of the parameter and editing its contents or by
using the pull-down menus.
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The parameters that can be changed in this window are:
1. units used for display of accelerations (‘Units for
accelerations’) (g, m/s2, cm/s2 or mm/s2);
2. units used for display of velocities (‘Units for velocities’)
(m/s, cm/s or mm/s);
3. units used for display of displacements (‘Units for
accelerations’) (m, cm or mm);
4. variable used for calculation of Fourier amplitude spectra
(acceleration, velocity or displacement);
5. damping level used in figures comparing the response
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spectra of two or more records (0, 2, 5, 10 or 20%);
6. line styles used for figures comparing the derived strongmotion parameters of two or more records (monochrome or
colour);
7. whether absolute time is reported on the graphs showing
acceleration, velocity and displacement time-histories (yes
or no);
8. whether to use logarithmic or linear x-axes for graphs
(logarithmic or linear);
9. whether to use logarithmic or linear y-axes for graphs
(logarithmic or linear);
10. whether to use period or frequency for graphs and
parameter display (period or frequency);
11. which variable to plot on maps displaying time-histories
(acceleration, velocity or displacement);
12. which component to plot on maps displaying time-histories
(Z, N or E);
13. whether to display range rings on maps displaying timehistories (yes or no);
14. whether to display metadata in title of figures (yes or no);
15. whether to display grid lines on figures (yes or no):
16. what COM port to use for dialling stations (COM1 is the only
option currently supported);
17. what baud rate to use for dialling stations (2400, 4800,
9600, 19200, 38400, 57600 or 115200);
18. length of pre-event time to use for calculating noise
estimate (‘Length of pre-event time’) in seconds (if this is
set to zero then a noise spectrum is not calculated). This can
be selected interactively by clicking on the ‘Select’ button,
see below;
19. corner frequency (‘fl’) in Hz of the bi-directional filter used
for high pass filtering time-histories (usually this is about
0.05Hz for records from CMG-5Ts and it cannot be less than
0Hz). This can be selected interactively by clicking on the
‘Select’ button, see below;
20. order (‘Order’) of the Butterworth filter used for high pass
filtering time-histories (the default value for the order is 2, a
higher order filter has a steeper transition band but requires
more zero padding and the filtering takes a longer time).
This can be selected interactively by clicking on the ‘Select’
button, see below;
21. frequency where cosine taper of low pass filter starts (‘fh1’)
in Hz (usually this should be about 50Hz for records from
CMG-5s);
22. frequency where cosine taper of low pass filter ends (‘fh2’)
in Hz (usually this should be about 100Hz for records from
CMG-5s);
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23. acceleration threshold to use within the computation of
cumulative absolute velocity (CAV) (this must be positive). A
commonly-used threshold is 0.025g [0.245m/s2];
24. the number of the peak to select for computation of the
sustained maximum acceleration and velocity (this must be
a positive integer). A commonly-used value is 3, denoting
the third peak;
25. acceleration used as the limit acceleration in the calculation
of bracketed absolute duration (‘Bracketed Absolute’) in the
selected units of acceleration. A commonly used limit
acceleration is 0.05g [0.49m/s2];
26. proportion of peak ground acceleration used as the limit
acceleration in the calculation of bracketed relative duration
(‘Bracketed Relative’). This must be between 0 and 1;
27. value of Arias intensity used as the lower threshold in the
calculation of significant absolute (effective) duration in the
selected units of velocity (see Bommer & Martinez-Pereira,
1999) (‘Significant Absolute (Start)’). A commonly used
lower limit is 0.01m/s;
28. value of Arias intensity used as the upper threshold in the
calculation of significant absolute (effective) duration in the
selected units of velocity (see Bommer & Martinez-Pereira,
1999) (‘Significant Absolute (End)’). A commonly used lower
limit is 0.125m/s;
29. proportion of Arias intensity used as the lower limit in the
calculation of significant relative duration (‘Significant
Relative (Start)’). This value must be between 0 and 1 - a
commonly used lower limit is 0.05;
30. proportion of Arias intensity used as the upper limit in the
calculation of significant relative duration (‘Significant
Relative (End)’). This value must be between 0 and 1 - a
commonly used upper limit is 0.95;
31. acceleration used as the limit acceleration in the calculation
of uniform absolute duration (‘Uniform Absolute’) in the
selected units of acceleration. A commonly used limit
acceleration is 0.05g [0.49m/s2];
32. proportion of peak ground acceleration used as the limit
acceleration in the calculation of uniform relative duration
(‘Uniform Relative’). This value must be between 0 and 1;
33. cyclic damage exponent to use for the computation of the
effective number of cycles. A commonly used value is 2;
34. period used as lower limit in calculation of spectral intensity
(‘SI limits Lower’). A commonly used lower limit is 0.1s;
35. period used as upper limit in calculation of spectral intensity
(‘SI limits Upper’). A commonly used upper limit is 2.5s;
36. period used as lower limit in calculation of acceleration
spectral intensity (‘ASI limits Lower’). A commonly used
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lower limit is 0.1s;
37. period used as upper limit in calculation of acceleration
spectral intensity (‘ASI limits Upper’). A commonly used
upper limit is 0.5s.
38. the material to assume for the computation of the drift
spectra (steel, R/C or other)
Clicking on the ‘Save’ button saves the chosen parameters to a
file called art_default.dat which is loaded each time ART is
used. The parameters are not automatically saved when the
window is close using the close icon; however, they are used
for the rest of the session.
3.2.3 Interactive selection of filter parameters
The
Order
and corner frequency
fl
of the Butterworth filter, as
well as the
Length of pre-event time
, can be set interactively.
1. Select a single stream in the centre panel of the main
window. Click Options.
2. In the
Options
window, beneath the legend
Length of
pre-event time
, click the Select button. A window will
pop up displaying the stream you have selected.
3. The top two graphs show the acceleration and
displacement time histories for the selected stream, with
the current low-pass filter applied.
4. The red line shows the current
Length of pre-event time
setting. Data before the line is used to calculate spectra
of ambient ground motion; data after it is treated as part
of the event.
Click in either graph to move the line. The spectra below
are updated automatically.
5. The plot at bottom left shows the Fourier amplitude
spectrum of ambient ground motion (in blue) and of the
event (in black), using the current filter settings.
The plot at bottom right shows the ratio between the two
spectra (
i.e.
the signal-to-noise ratio). The horizontal red
lines represent signal-to-noise ratios of 2:1 and 1:2; the
blue lines represent ratios of 3:1 and 1:3.
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