github.com/usgs/prismU.S. Geological Survey Earthquake Science
Center
Processing and Review Interface for Strong Motion Data (PRISM)
Software Version 2.0
Main Features
Earthquake Science CenterU.S. Geological SurveyMenlo Park,
California
http://earthquake.usgs.gov/
AbstractErol Kalkan ([email protected]), Jeanne Jones,
Christopher Stephens, Peter Ng, Jamie Steidl, Jeff Brody, and Lind
Gee
PRISM automates the processing of strong-motion records by
provid-ing batch-processing capabilities.
The software consists of two components:
- Platform-independent, modular, extensible and open-source;
- Customizable processing parameters with a con�guration
�le;
- Phase-time and maximum amplitude picking;
- Time-domain mean-removal, integration and di�erentiation;
- Frequency-domain resampling;
- Acausal bandpass �ltering;
- Baseline correction determined from the velocity time series
and re-moved from the acceleration time series in time domain;
- Filtering performed on the acceleration time series in time
domain;
- Generation of products that include compatible acceleration,
veloc-ity and displacement time series, response spectra, Fourier
amplitude spectra, and standard earthquake-engineering intensity
measures;
- Log �les for quality control and reproducibility;
- For input, currently uses Consortium of Organizations for
Strong-Motion Observation Systems (COSMOS) V0 input format with
meta-data in COSMOS headers; and
- Products in COSMOS data format (V1, V2 and V3).
A graphical user interface (GUI) for manual review, edit and
processing.
A record processing engine (command line interface) com-posed of
modules for each pro-
cessing step.
1) Pseudo acceleration, veloc-ity and displacement spectra at 2,
5, 10 and 20% damping,2) Fourier Amplitude Spec-trum, and3)
IMs:
Volume - 3 Processing
- Arias Intensity- Bracketed Duration - Duration Interval -
Response spec. intensity - RMS Acceleration- CAV
Corrected acceleration
Calculate FFT
Response spectra
V3 Process
Select spectral amplitudes for given
periods
Calculate peak response
For each damping value
For each period
Fourier spectrum
What’s New in PRISM 2.0- Frequency-domain integration;
- Frequency-domain decimation;
- Auto-detecting spikes and removal;
- Signal-to-noise ratio (SNR) thresholding; and
- Auto-detecting bandpass-�lter corner frequencies.
Volume - 1 Processing
Step - 1: Resampling to 200 sps (if needed)Step - 2: Event onset
detectionStep - 3: Pre-event mean removalStep - 4: First order
baseline cor-rection (velocity domain)Step - 5: QC Step - 6a:
Bandpass �lter with acausal �lter (acc. domain)Step - 6b: Adaptive
baseline cor-rection (ABC) Step - 7: Compute acceleration, velocity
and displacement.;Step - 8: Decimate to original sampling rate (if
needed)
Raw Data Trace
Convert counts to g Convert counts to cm/sec2
Uncorrected acceleration
cm/sec2g
V1 Process
Units ofcm/sec2 or g
Remove mean
Despike?
Remove spikes
Yes
No
Uncorrected acceleration (V1)
Find event onset
Remove pre-event mean
Integrate to velocity
Find best fit trend
QC velocityFail Pass
Adaptive baseline correction (ABC)
Acausal bandpass filter acceleration
Integrate velocity to displacement
QC velocity & displacement
Able to run ABC
No
Yes
Corrected acceleration Velocity Displacement
V1 and V2 to Trouble Folder
V1 to Trouble Folder
Pass
Fail
V2 Process
Found onset
Yes
No
Integrate acceleration to velocity
Differentiate best fit trend
Remove best fit trend from acceleration
Acceleration with pre--event mean removed
Copy of acceleration with pre-event mean
removed
Trend to remove from acceleration
Integrate acceleration to velocity
Volume - 2 Processing
PRISM 1.0 vs 2.0 Processing
0 20 40 60 80 100 120Record No.
0.1
1
10
100
Freq
uenc
y, H
z
2014 M4.4 SD Palos Earthquake
PRISM 1 high-passPRISM 1 low-pass
PRISM 2 high-passPRISM 2 low-pass
0 10 20 30 40 50Counts
Take-home Message
10-2 100 102
Frequency, Hz
10-10
10-8
10-6
10-4
10-2
100
102
Four
ier A
mpl
itude
Spe
ctru
m, c
m/s
2 .s
NCN016-n.711.HNE | dt1=0.005 s; dt2=0.005 s
PRISM 1 (passband = 0.1 to 40 Hz.)PRISM 2 (passband = 0.1 to
25.2 Hz.)
-200
0
200
NCN016-n.711.HNE | dt1=0.005 s; dt2=0.005 s
Acc
., cm
/s2 PRISM 1 PRISM 2
-200
0
200
Acc
., cm
/s (PRISM 2 - PRISM 1)
-50
0
50
Vel
., cm
/s
-50
0
50
Vel
., cm
/s
-20
0
20
Dis
., cm
0 20 40 60 80 100 120 140 160 180Time, s
-20
0
20
Dis
., cm
Comparing PRISM 1.0 and 2.0 results for component HNE of station
NCN016 record from the 2014 M6.0 South Napa earthquake.
Frequency-domain Integration
Frequency-domain Decimation
Spike Removal
Auto-detect Passband Corners
-5
0
5Station: IU.AFI | Comp: HN1 | 200 sps
Acc
., cm
/s2
-0.05
0
0.05
Vel
., cm
/s Frequency-domain int.Trapezoidal int.
-5
0
5 10-3
Difference in PGV = 2.21%Vel
., cm
/s [Frequency-domain int. - Trapezoidal int.]
-5
0
510-3
Dis.
, cm
0 5 10 15 20 25 30 35 40Time, s
-5
0
510-4
Difference in PGD = 0.01%Dis.
, cm
0 200 400 600 800Record No.
0.1
1
10
100
Freq
uenc
y, H
z
2014 M6.0 South Napa Earthquake
PRISM 1 high-passPRISM 1 low-pass
PRISM 2 high-passPRISM 2 low-pass
0 200 400 600Counts
Comparing PRISM 1.0 and PRISM 2.0 passband corner frequencies
for the 2014 M6.0 South Napa and 2014 M4.4 SD Palos earth-quakes.
In PRISM 1.0, corner frequencies are retrieved from a look up table
based on the earthquake magnitude. In addition to this, PRISM 2.0
also o�ers auto -detecting corner frequencies.
10-2 100 102
Frequency, Hz
10-20
10-15
10-10
10-5
100
Four
ier A
mpl
itude
Spe
ctru
m, c
m/s
2 .s
High-pass:0.10 Hz & Low-pass:60 HzSignalNoiseSignal
smoothNoise smoothLow-pass cornerHigh-pass corner
Detects appropriate bandpass �lter corner frequencies to be used
for Butterworth �ltering by using the signal's frequency
content.
Noise and signal spectra are smoothed using Konno-Ohmachi
window.
Replaces spikes (outliers) exceeding the dynamic threshold value
by in-terpolating among previous and subsequent data points.
0 10 20 30 40 50 60 70 80 90 1000
10
20
30Original Signal
0 10 20 30 40 50 60 70 80 90 1000
10
20
30Spike Removed Signal
PRISM 2.0 provides greater �exibility and increased processing
accuracy for strong motion data.
Integrates signal in frequency domain by dividing its Fourier
spectrum with -iw.
0 2000 4000 6000 8000 10000 12000-5
0
5
Acc
eler
atio
n Tonga Record, HNN
Original (100 sps)
0 0.5 1 1.5 2 2.5# 104
-5
0
5
Acc
eler
atio
n
Re-sampled to 200 sps
0 2000 4000 6000 8000 10000 12000-5
0
5
Acc
eler
atio
n
Decimated to 100 sps
0 2000 4000 6000 8000 10000 12000Time-step
-1
0
1
Diff
eren
ce
# 10-4
Frequency domain decima-tion module reduces the sam-pling rate
of a re-sampled signal to its original sampling rate.
PRISM 2.0Note: No �ltering or baseline correction applied.
Di�erences between PRISM 1 and PRISM 2 processing
Di�erences between PRISM 1 and PRISM 2 processing
Di�erences between PRISM 1 and PRISM 2 processing
Poster Number 154
