Good morning, and welcome to the August 8th – August 9th version
of the Earthquake Science seminar. And we’re pleased to have you.
Next week, we have a very special speaker.
Our own Jack Norbeck will be talking about hazard of induced earthquakes.
And before I introduce the speaker, I’d just like to let you know that we’re
planning to have lunch with Erol after his talk – probably about quarter to noon.
So most of you know Erol, looking around in the room.
But for those of you who may not know Erol,
Erol has both his bachelor’s of science and his master’s
in civil and structural engineering and engineering seismology from the
Middle East Technological University and Bosphorus University.
His Ph.D. in structural engineering is from UC-Davis,
and he has a minor in geotechnical engineering.
He did a postdoc at UC-Berkeley and was a seismologist
at the Geological – sorry, the California Geological Survey
for about four years before he joined the USGS in 2008.
He’s been a member since that time in the National Strong Motion Project,
and he’s worked on such things as instrumenting
the Veteran Affairs hospitals for alerting that system
for earthquake damage and earthquake early warning.
And he’s played many roles in the American Society of Civil Engineers.
So, Erol?
- Thank you so much for the introduction.
I hope you all hear me well? Okay.
So my name is Erol Kalkan. I am a structural engineer
with the Earthquake Science Center. Before, you know, starting,
I would like to, you know, acknowledge my co-authors and my colleagues.
Jeanne and Peter – they are sitting right on the back.
They work for the Western Geographic Center.
So they are our very talented – you know,
the programmers that basically make this software happen.
And Chris is the data manager for NSMP – National Strong
Motion Project. And today, talk is going to be on software.
I find myself a little bit difficult to actually present the software,
but I’ll do my best. So this software is – we develop
for processing strong ground motions, you know, automatically and
some really neat features and somewhat interesting –
the modules that I will try to, you know, show you guys.
So, you know, the first thing I would really want to say –
thank you for the members of the NSMP working group,
especially David Oppenheimer who initiated this project
and the name – you know, the PRISM.
And Lind Gee has been very supportive for – you know,
for this project basically all the way through here and,
you know, the providing it – you know, enough funding.
And like to thank Dave Boore for sharing his –
you know, the Fortran codes for filtering.
Joe Fletcher and Vladimir Graizer for many –
you know, the discussions on signal processing.
Jamie, Brad – you know, Bob Darragh and Tadahiro Kishida.
They were really helpful for reviewing our – you know,
the publications and providing, you know, the comments and –
very constructive comments and suggestions.
And finally, I would like to thank to NSMP technicians
who install and maintain the strong motion network
and those involved in collecting and vetting the strong motion data.
So with that said, here’s the outline of my talk.
Just want to first explain you why we started this project.
And then give a snapshot of PRISM. And then I want to compare
the PRISM with other softwares available in the market.
And then the integration of the PRISM with the earthquake –
you know, Advanced Quake Management System of the USGS.
Like to introduce you to data format that we used.
And then we’re going to look under the hood
about actually PRISM processing engine works.
We did very comprehensive testing that I want to mention about that.
And then I’m going to introduce the graphic user interface
of PRISM software.
And then finally, I’ll show you our documentation, and in a couple of slides,
show how we can run the PRISM processing engine.
And finally, updates and my concluding remarks.
So the primary motivation is that – you know, NSMP has been
deploying more and more stations every year.
And the – processing ground motion has been a manual process,
you know, by our – you know, the expert people here.
You know, as we get more records in-house, so automatic
strong motion record processing becomes a – you know,
the essential part of our – you know, the daily routine.
With that saying, so we like to have the expert review
only limited to selected very significant events or the records that,
you know, automatically process but have some –
you know, the issues that needs to be manually addressed.
So, so far, you know, since 1992, USGS had been using venerable processing
software, BAP, which is the Basic Strong-Motion Accelerogram Processing.
It’s, again, written in-house at the USGS.
But this – you know, the Fortran codes become outmoded.
So it doesn’t actually allow for automated processing.
So in a nutshell, so PRISM is – basically we got the raw acceleration
data into the system, and we have the – you know, the product distribution.
We primarily provide acceleration, velocity, displacement –
those are all corrected waveforms, and we provide, you know,
pseudo acceleration, response spectrum, velocity, and displacement.
Response spectrum, we provide Fourier spectrum
and a bunch of earthquake intensity measures.
So it’s fully – it’s a modern software. It’s completely Java-powered.
Its design is based on API, which is an application
programming interface, which allows actually PRISM processing
engine works, you know, seamlessly with the graphic user interface.
It has two modules. One of them is the batch processing
engine where we do, you know, the automatic processing.
We also have a review tool, which is the graphic user interface,
where the user can, you know, grab it – a bunch of records and, you know, do –
manipulate them – you know, do processing manually.
So PRISM both is processing engine and the review tool
is very easy to install and run as a standalone system.
So because it’s Java-based, it works on, you know,
the Mac operating system, Windows, or, you know, the Linux computers.
So here I’d like to compare PRISM with other, you know,
available software in the market.
PRISM definitely joins, you know, a suite of tools also used with
other processing codes. But we certainly have some really unique
new features that doesn’t present in the – you know, in others.
So in terms of – you know, so our software is completely free, you know,
and open-source, you know, similar to the older – the USGS software BAP.
There are two commercial softwares –
SeismoSignal and Seismogram 2K from Europe.
So SeismoSignal is – well, it’s not free. It’s not open-source.
It doesn’t allow for batch processing.
Well, Seismogram 2K is free, but the source is not open.
So in terms of graphic user interface,
except for BAP, you know, all other software has that.
So we use phase picking – picking through, you know,
the P wave arrival time, we use that for ground motion processing.
We thought it was very useful to have a –
you know, the better or more reliable processing.
So only PRISM and, you know, the Seismogram 2K does that.
So in terms of the platforms, so we are platform-independent.
You know, the BAP works on, you know, the Windows operating system.
SeismoSignal, again, works only on Windows operating system.
Seismogram 2K is Java-based, so it can work on three operating systems.
So in terms of updates and support, you know, there’s no updates for BAP,
but the other – you know, the three softwares, they have the
updates and support. So that’s just basically how we compare with others.
So the whole idea to PRISM is making all the strong motion data
coming to USGS process automatically.
So the USGS is using Advanced Quake – the management system.
And so this system detect the earthquake, you know,
collect all the waveforms. And then, you know, well,
thanks to Tim MacDonald, so the AQMS is fully integrated with PRISM.
So when the data comes, so the PRISM – you know,
kicks in, process all the – all the records automatically
without any, you know, interference.
So that was the whole idea why – you know, why we started this project.
And I’m actually really glad to see that it’s – you know, the final is,
you know, up and running and fully integrated with the AQMS.
So PRISM uses standard COSMOS data format.
So these are the Volume 1, or what we call it, V1.
These are uncorrected acceleration.
So these are all our – you know, the products.
And we have the Volume 2, where we have the
corrected acceleration, velocity, and displacement time series.
And then the Volume 3 is the response spectrum, Fourier amplitude spectrum,
and engineering intensity parameters, which I’m going to explain them shortly.
So if you look at the – you know, how actually the processing occurs,
so the PRISM processing engine – first I would like to give all the –
you know, the key features.
And I want to show all the – you know, the – how the processing flow works.
It’s fully automated, as I mentioned.
It’s platform-independent, modular, extensible, and open-source.
It doesn’t depend on any closed-source or any licensed software.
So processing engine implements the – you know, the API to allow,
you know, incorporation of alternative implementation steps.
That’s – you know, that’s very typical with all the modern software today.
So we have a customizable configuration file that the user can, you know, go and,
you know, change some parameters for the automated processing.
So we collapse everything into this – you know, the configuration file.
So it’s really flexible.
And it does P wave arrival time picking.
So currently we have two pickers implemented, and the user can,
you know, decide which one they’re going to use in this configuration file.
So we have the PphasePicker and the AIC picker.
So PRISM also do a maximum amplitude picking.
We do, you know, integration and differentiation, obviously.
Right now everything is in the time domain.
In terms of digital signal processing, we use frequency domain
zero-padding for resampling. We use acausal bandpass filtering.
And then filtering is, you know, performed on
acceleration – you know, the time domain.
So our products, you know, includes compatible acceleration,
velocity, and displacement time series. So that means, you know,
one can get the acceleration records and, you know, integrate to get the
velocity and integrate, you know, the displacement and, you know,
vice-versa, go back by differentiating, and then get the same acceleration.
So I’m going to explain that, you know, in a little, but not every – you know,
the data produces, their products are not – they’re compatible.
So compatible data products basically includes initial values required,
which we save them in V2 – you know, the Volume 2 file in header information.
So we can produce – we can go back
between acceleration, velocity, and displacement.
So PRISM creates really nice, you know, the list of log files.
So this way, like, every step of the processing can be traced.
So, as I mentioned, for input, we are currently using, you know,
the COSMOS V-zero input format.
So V-zero is – the raw data comes to PRISM is basically in counts –
not even – not even in, you know, the physical units.
So as I mentioned, the products are in COSMOS data format,
Volume 1, Volume 2, and Volume 3.
So the Volume 1 processing is the simplest, you know, start.
We got the raw data coming to PRISM.
So we convert the counts into physical units,
and then we remove the mean from the entire time series.
We don’t do instrument response correction, you know,
for there isn’t that – you know, the cutoff frequency of the
low-pass filter that we use is lower than that of the natural
frequency of the accelerometer. With that saying, you know,
PRISM doesn’t process any records if there’s something
where it is less than 50 sample per second.
So Volume 2 processing is actually where all the –
you know, the magic happens. So this is much more complicated.
So the first, once we get the data, we check the sampling rate.
If anything – you know, less than 200 sample per second,
we resample it to 200 sample per second.
And then we do event onset detection to find where the –
you know, the P wave arrival time is. And then we remove the pre-event mean
from the – you know, from the rest of the record.
And then we apply, you know, the baseline correction,
first- or second-order by fitting a first- or second-order polynomial to velocity.
And then we take the derivative of the baseline correction from acceleration.
And then we go back, and then we do some QC to make sure that, you know,
the velocity – it oscillates in the beginning. And at the end of the
velocity oscillate around zero. So those are our physical constraints.
So we do bandpass – once the QC pass, we do bandpass filter, the acceleration.
And then we do – you know, if everything goes well,
we integrate to get the velocity and displacement.
You know, sometimes these initial baseline correlation is not sufficient.
But in that case, our QC fails, and then, you know, the system
starts a more complicated baseline correction algorithm
which we call it adaptive baseline.
So I’m going to go back to adaptive baseline in the next slide, but this is –
let’s assume that, you know, we finished the Volume 2 processing successfully.
And then that product goes back to the Volume 2 – Volume 3 processing.
So here we have the corrected acceleration,
and then we calculate the pseudo acceleration, velocity,
and displacement response spectra for 2, 5, 10, and 20% damping levels.
And then we compute the Fourier spectra.
And then we compute a series of
earthquake engineering intensity measures.
These are the default intensity measures in COSMOS Volume 3 data format.
So we calculate the Arias intensity. We calculate the, you know,
strong motion duration, the bracket duration,
duration interval, response spectrum intensity,
root mean square acceleration, and also cumulative absolute velocity.
So all this – the outcomes goes back to the Volume 3 sent as ASCII file.
So want to come back to adaptive baseline correction.
You know, sometimes records may have, you know, step-like offsets –
you know, the spikes in the baseline, or they may be contaminated by,
you know, some instrumental noise or some rotational, gravitational, you know,
effects or sometimes, you know, the static – fault displacement.
So this case, you know, the PRISM regular processing
may not be sufficient to correct for such distortions.
So here is – I would like to give one example.
So we have the acceleration record, you know, after pre-event mean removal.
So we do – we apply our initial baseline correction.
So as you see – I’m sorry.
We just integrated the pre-event mean removed acceleration to velocity,
and you can see, you know, the trend at the – at the tail of the record.
So when we apply, you know, initial baseline correction,
you know, we fix that distortion. But in this case, the beginning of the
record has, you know, some distortions.
So basically, the record failed our QC because the velocity is – the mean
average velocity in the beginning of the record is not close to zero.
So once the record – you know, fails in QC,
it goes back to our, you know, adaptive routine.
So the adaptive baseline correction is based on the idea that, you know,
we can divide the waveform into multiple segments
and do some fitting of those multiple segments.
So the idea has come, you know, way back in 1979 from Vladimir Graizer
published a – you know, the paper, and then – and then the folks in
Caltech and then, you know, Boore has published another paper in 2001.
The whole idea is, you know, get the record and divide into
multiple segments and, you know, fit, you know, different polynomials
to have – to have a better baseline correction instead of, you know, like,
a first-order or second-order simple polynomial for the entire record.
So we developed adaptive baseline correction, which we call it ABC,
you know, following the – Iwan’s method.
So in ABC processing, we fit a nth-order polynomial to the
beginning of the record and also the end of the record, where we know that,
you know, the beginning shows, you know, physically at zero,
and then the record should go back to –
you know, oscillate around zero. Those are our physical constraints.
And then these two polynomials, we join them with a cubic-spline
in the beginning part – in the middle part.
So here’s the flow chart of our adaptive baseline correction.
It’s a little bit complicated. It’s an integrated procedure.
The challenge here is that, to find out, you know, what part of the waveform is
going to be at the beginning, the end and, you know, the middle sections.
So the beginning part is – you know, it start from the zero, and then we
choose the pre-event – end of the pre-event duration, or the onset time
of P wave arrival, as the first segment.
So that’s where we are actually fitting the first polynomial.
And then the challenge is deciding on the end segment of the waveform.
So here is – we have the, you know, t-sub-2.
That’s the beginning of this end segment.
And in ABC processing, so we basically are iteratively changing this t-sub-2
to have a – you know, to come up with the optimal baseline correction fit.
And in between those two polynomials, we have, you know, the cubic-spline.
So not only the ABC is iteratively changing the beginning of the
end segment that we’re going to fit a polynomial, but also changing
the polynomial orders to come up with, you know, the best solution.
So this is an iterative procedure all the way – you know, it looks like it’s
going to take time, but it’s like a – you know, it works extremely fast.
So at the end of this adaptive baseline correction, we come up with the
best solution for the baseline and we – in the velocity domain, and then we take
the derivative, go back to acceleration, and remove it from the acceleration.
So once we do that, we do all these – you know the quality check again.
And if everything pass, you know, so the record –
the PRISM goes back to the next record.
So if something fails, it went with the adaptive baseline correction.
So PRISM flag that record as a trouble and put it in the trouble folder.
So that’s where the manual processing is needed.
So here is – I would like to show you one – you know, the weak motion
that we process using PRISM from 2014 South Napa earthquake.
The red lines are the PRISM products, and the black is the uncorrected
acceleration at the top panel and the uncorrected –
basically the velocity in the lower – I just, you know, integrate the
uncorrected acceleration just to show the trend in the velocity.
So once we, you know, apply the PRISM, so this record
didn’t go to adaptive baseline correction, so basically, our initial baseline
correction was sufficient, so the – you know, once we done
with this record, so we have a – you know, the nice signal and –
yeah, so that’s what it is for this slide.
So we have many, many examples in our – you know, the open file reports
show how basically the PRISM generates results.
That was just one example.
Here I’d like to show you how fast actually the PRISM works.
So we did a runtime performance test using,
you know, the [inaudible] desktop computer.
So it’s a 2.6 gigahertz CPU with 16-gigabyte RAM.
So we processed the South Napa records, which has about –
more than 700 channels. And we also picked two –
you know, the small-magnitude events around 100 channels each.
So if you look at those small-magnitude events, so the passing grade is 100%.
So PRISM processed them – all the records without any problem.
When you look at the processing time, you know, for each channel,
it’s less than half a second. So the data comes extremely fast.
You know, the process – we have all these data products
right in the – you know, the output folders.
So in the South Napa case, you know, the processing time is,
again, less than a second. It’s basically 0.8 seconds
because some of the records required, you know, the ABC processing,
which may require a little bit more time.
But overall, you know, for 700 records,
we are practically done, you know, less than 10 minutes, everything is ready.
So we compare PRISM first with the BAP as well as
the California Strong Motion Instrumentation Processing.
So it’s like – because every – you know, the BAP has its own –
you know, the flavors. The same thing with the
CSMIP processing. So it’s not each software is exactly the same.
So it’s kind of like comparing, a little bit, apples to, you know, the oranges.
You know, nonetheless, we did a series of benchmark tests.
So we have a dedicated open file report showing all the –
you know, the comparison.
And we tried to match the processing parameters between, you know,
the BAP, the CSMIP, and the PRISM as closely as possible.
Although, you know, we were expecting to see some difference because there are
some, you know, fundamental differences in the techniques that we used.
So one of the main differences here, you know, among many –
so in BAP processing, low-frequency filter is applied in time domain.
And at high frequencies, the cosine taper is used in frequency domain.
So in CSMIP processing, so initial long-period filter is applied to
the instrument-corrected acceleration. And then, you know, the velocity
and displacement are subsequently computed by integrating the
acceleration and then filtered again by using the same long-period filter.
So in contrast, you know, the PRISM applies filtering
to corrected acceleration only. And the velocity and displacement
are obtained by, you know, integrating the filtered acceleration.
So this basically give us a – this process leads to a
compatible acceleration, velocity, and displacement time series.
So, you know, we did all this testing – the first – you know, we got a –
around, you know, the [inaudible] records.
And we look at very detailed – like, how, you know,
the PRISM processing compare with the BAP and CSMIP processing.
So for that purpose, we first compare the peak values.
And then we computed the, you know, coherence – you know,
the cross-spectrum phase, cross-correlation of the time series.
We also compared the Fourier amplitude spectrum between,
you know, the different ground motion processing routines.
And then finally we computed and compared the spectrograms
of power spectra of acceleration, velocity, and displacement time series.
So I’m not showing all the results here, but everything is,
you know, in our open file report. But here is just, you know, one example.
Here is the PRISM versus BAP processing.
So we picked this 2005 magnitude 5 earthquake from Samoa.
So this record is 100 sample per second.
And the PGA occurs at very high frequencies.
So this is one of our – you know, the test record.
So when we do the PRISM versus BAP comparison – so the first
panel show the acceleration time series. These are all processed.
And the following panels show the difference between the acceleration.
And then, you know, the same thing for the velocity and displacement.
So overall, you know, except in the final few seconds of the process record,
you know, the BAP and PRISM is basically producing the same waveforms.
And the difference between the peak values are –
well, we haven’t seen any difference in the PGA and PGV, and peak
ground displacement difference is less than 0.1 second – 1%.
So we did, you know, similar comparisons with many other records,
but here’s one example from South Napa earthquake – Napa College.
So we compare our processing with the CSMIP processing.
You know, peak values, again, you know, very close to each other.
So the difference is around, you know, the 1%.
But we – you know, we see some, you know, small variations in the acceleration
time series and, you know, the much less on velocity and displacement.
So these are – we thought these are all, you know, the possible –
because we are using, you know, different techniques for processing than,
you know, what – you know, CSMIP does.
So after looking, you know, at those records individually,
much details, you know, with the feedback from
the NSMP working group, we conducted a statistical evaluation.
So this time we collected more than 1,800 V1 records
from the Center for Engineering Strong Motion Data website.
So that’s the website operated by CGS and USGS.
So we pick eight earthquakes that occur in California between 2005 and 2006.
So this is the distribution of our – you know, the events with the
moment magnitude and epicenter distance.
So we have a bunch of records, you know, in the near field as well as,
you know, the far field where we have the lower,
you know, signal-to-noise ratio.
And then we compare – we process them with the PRISM
and compare how our products compare with the CSMIP processing.
So we computed misfit between two times series by comparing, again,
the peak values, as well as normalized Euclidian distance
between acceleration, velocity, and displacement time series.
We also did moving window root mean square level of acceleration,
velocity, displacement time series. It’s actually – it’s really difficult
to compare two time series, when you look at – I mean, it’s easy to compare the
peak values, but how about the whole – you know, the time series.
That’s why we used these L2 norm as well as the moving window RMS.
So among those eight records, here is, you know,
one example from, again, the South Napa earthquake.
So what we are looking, on the Y axis, is the peak values –
peak ground acceleration, velocity, and displacement.
And on the X axis, I show the difference between
the PRISM processing as well as CSMIP processing.
So I color-coded – so everything blue is the difference in the PGA, PGV,
and PGD is within 1%.
And, you know, similarly, orange is between 1 and 2%.
Yellow is between 2 and 3%, and then the red is, you know, 3 to 4%.
And the vertical line showing the median value, and then
the standard deviation is shown by the – you know, the horizontal.
So overall, you know, most of the data is collected
between minus 1 and, you know, the 1% difference.
So for the measure of two of the records, you know,
the difference overall between 1 and 2. And then the other seven earthquakes,
basically, you know, provide the same kind of results.
And now, when we look at the overall – you know, more than 1,800 records,
for 80% of the records, PRISM provides peak values,
you know, equal or less than 1% of the CSMIP values.
So this – we did this testing to give a confidence to the
engineering community that, you know, what we are processing here is,
you know, not much difference than what the CSMIP processing does.
So this part so far – done all the – you know, the automated processing part.
So as I mentioned, so PRISM has also graphic user interface
for manually editing the records if needed.
So PRISM review tool is – these are the features.
It’s a desktop application. It’s a standalone application.
You don’t need to install the – you know, the processing engine.
Again, using the COSMOS data sets.
But it – because it’s based on the API, design is
basically using all the tools that – what we have in the processing engine.
It has multiple viewers and editors for handling seismic and,
you know, the spectral – you know, the trace data.
It provides template processing, so if you – if you can create your
template and apply the same template for, you know, the multiple records
without each time going and changing the parameters.
Has a customizable, you know, graphic user interface.
And it’s platform-independent.
So here’s the main – you know, the interface of the review tool.
So on the left side, you have your – you know, the navigation pane.
You can see all the – you know, the – all the records. You can move them around.
In the middle, you can see the – you know, the wave traces.
And what is really neat is that Pete put a really nice feature on the
last panel – the new channel – you can see all your metadata there –
you know, the earthquake information, you know, the sampling rate,
your station number, you know, so on and so forth.
So when you look at the seismic editor, so you have your acceleration,
velocity, displacement. You know, you can choose your –
you know, the baseline correction parameters here.
You know, like, the application range, and then, once you click the Commit,
so it’s basically [inaudible] baseline correction –
basically baseline from the – you know, the record.
Again, what’s really nice is that, on the right panel,
this is the history of your processing.
So you can – by clicking, you can go back to your – you know,
the previous step. So you can go back to all the way up
and then – you know, to start over. So it’s quite flexible, the interface.
And finally has the seismic editor for your spectrum where you manually –
you can click on the – on the screen and, you know,
come up with your filter range and apply your filtering.
So this is all about, you know, how we do the manual processing.
So we published, so far in 2017, a very comprehensive report
on the batch processing part. And then another open file report
fully explaining, you know, our testing with – comparing with
the BAP as well as the CSMIP ground motion processing.
We published a summary paper in Seismological Research Letters,
you know, a few months ago. And PRISM, right now, is at GitHub.
The whole source code is available under USGS/PRISM.
We also have a dedicated website under USGS research, where we
tried to put, you know, the more information for the – for the user.
We have links to our – you know, the documentation, as well as –
as well as link to source code.
So if you look at that website, we provided very simple four-step
procedure to how to run PRISM processing engine if you want to test it.
So if you click on the second one – you know, Download PRISM Processing
Engine Executable File, which is a JAR file, and then we provided examples.
So there’s a PDF showing – it’s actually – it doesn’t even take, like,
a half a minute to, you know, read it and implement it.
So when you download our – the folder – the ZIP folder,
so you have – the JAR file is available here, and then our –
you know, the four-step procedure as a PDF.
We have the configuration file folder where the XML files stays.
So you don’t need to change that unless, you know,
there is a need to change some of the – you know, the filtering or some of –
you know, P phase picking parameters or some other parameters.
And then we have the computed parameters.
So in the “in” folder, we have the input motion as V-zero files.
And when you, you know, run it on the terminal – so the folder structure is
going to have all these outputs for each station, you know, nicely organized.
And then, when you look at the – each station, you have your
V-zero folder, V1 folder, V2, and V3 folder with all the products.
So, so far, that’s, you know, what we have done with PRISM version 1.
So we would like to continue with PRISM 2.
So we have some – you know, the proposed updates
for FY – fiscal year ’18.
We would like to add a new feature for pre-screening V-zero files.
And we would like to reject any files when the signal-to-noise ratio less than 3.
So we don’t want to actually – you know, to process the really noisy records.
And another feature that we want to implement is that right now,
the corner filter – corner filter – the filter corners that we use for [inaudible] filter,
we have a lookup table based on magnitude of the earthquake.
So they are really conservative values. So we would like to get rid of that.
Instead, we want to look at the frequency content of the record
to come up with, you know, what corner filters that –
the corner filter frequencies that we need to use for filtering.
So this is – we thought these are – you know, our high-priority updates.
So in addition, we’d like to implement frequency domain decimation algorithm.
You know, as I mentioned before, everything less than 200 sample
per second, the PRISM first resample the record to 200 sample per second
to eliminate, you know, numerical errors with the differentiation and integration.
So – and that keeps the waveform like that, you know, until – and it ends.
So we – you know, based on feedback from NSMP working group, again,
we want to – so there is a demand to bring back the original sampling rates.
So to do that, we would like to
implement a frequency domain decimation algorithm.
And then, as I mentioned, our integration and differentiation
is currently in time domain.
We would like to move it to the frequency domain, again,
to further reduce the numerical issues – numerical – you know, the errors.
And finally, you know, PRISM only accept V-zero COSMOS data format.
That’s kind of like limitation. We would like to have some
conversion tools for different input formats, you know,
similar to COSMOS – you know, the converter – so the user doesn’t have to
have, you know, the V-zero – COSMOS V-zero data format to use PRISM.
So our dream is, bring the PRISM 3 to the cloud,
and hopefully in the, you know, coming years.
And these are my concluding remarks. So we believe the – you know,
that it will offer a very robust automated processing –
ground motion processing software, you know, for use by, you know,
engineering applications and, you know, seismological studies.
So we realize that, you know, there is no unique way to process ground motion.
So we cannot that, you know, we are doing the best.
But we use, you know, mostly accepted – you know, the procedures, you know,
developed over the years by, you know, the Tony Shakal and his group.
You know, and then, you know, USGS folks, as well as,
you know, the other – you know, the COSMOS partners.
So, you know, all of the essential steps apply in PRISM, you know,
whether automatic or manual, are documented as, you know,
ASCII file headers of the processed time series.
We know this is very important. So we don’t want to give a black box.
So actually, once the processing is done,
so user have all the information – you know, what parameters are used.
So we try to provide as many information as possible
in the header of our products.
So these are the references cited during my presentation.
And, you know, the credits goes for the – for the logos that I used.
So that’s basically – wrap up my presentation, and I would like to
thank you for your time and for coming here and as well as for your attention.
[ Applause ]
- Thank you, Erol. It’s really nice to hear that –
although BAP was a very useful product, that it’s now
been superseded by something that will automate the process.
I remember waiting quite a while to get records using BAP, and so it’s really nice
to hear about new software that will do that very quickly and automatically.
Are there some questions?
- Hey, Erol. Thanks. That was a really nice presentation.
So just a couple things. One, I think it would be great
for your 2.0 to intake other data formats, which I think you …
- Right.
- And so then, to use this, you would download the V-zero separately,
and then process it all locally. Is that correct?
- Well, the processing engine is implemented to AQMS.
So AQMS is providing all the V-zero files automatically.
There is no … - Oh, okay.
- There is no intervention on that part. - So you don’t have to download
the files independently. It’s … - For manual processing, yes.
You know, you need to download the V-zero – you need the V-zero files.
- So you also showed a couple of your test data sets or examples.
Do you – would you have any of those available just to use?
Or you would advocate that you should do the –
run PRISM ourselves? [chuckles]
- For testing one? - No. Just for – I mean, you’re
producing a lot of really nice data sets. Do you have those personally available?
- Oh, yeah, yeah. We have … - Like, the South Napa.
All the processed data that you’ve done. - Right. Yeah. Yeah. Everything is –
you know, we can definitely provide it. Well, actually it’s a good point.
Maybe we can put all onto the website that, you know, a user can
get the whole Napa waveforms. - Right.
- Like V-zero files, and then they can do their own …
- Yeah, yeah. Okay. - … you know, processing. Yeah.
- Great. - That’s very good point. Thank you.
- Thank you.
- Erol, you mentioned that you’ve done a lot of testing to convince
the engineering community that PRISM is working.
Have you heard back from them?
Do they accept PRISM, and do they plan to use it?
- Yeah, that – well, that’s an excellent point. So that’s – actually, that’s why
we put together about this 150-pages-long open file report.
I presented PRISM during AGU. I haven’t got a chance to
go to engineering community yet, you know, to make presentations,
but that’s the plan. We put the PRISM, you know,
up in ResearchGate, you know, a couple of, you know, the websites.
We are getting, you know, a lot of hits and then, you know, the questions.
I believe people are, you know, using it.
But one of the downside is that we are really limited to the
COSMOS V-zero format, which has quite a bit of header information,
you know, including, you know, earthquake magnitude used to be there,
you know, among many, many others.
So we are hoping that, with the PRISM 2, once we double up those
conversion tools, then the engineers will be much more interested in using it.
And our graphic user interface, we are doing a second update on that,
so we haven’t released it yet.
But Pete and Chris, they’ve been working on that very hard.
So it should be done, you know, in a couple of weeks.
So once it’s done, we’re going to put that on GitHub and our – you know,
the USGS website as well. I think that will bring more interest
from the engineering community that they can see and, you know,
do a manual processing.
- Could you tell us … - Oh, sorry.
- Perhaps you mentioned it but I – and I missed it, but suppose a magnitude 6
earthquake occurs in the Bay Area. How quickly can the data be processed?
Is it limited by the delivery of the accelerogram data itself?
And what kind of lag time is there? - Yeah, that’s an excellent question.
Maybe Tim can tell us how quickly the AQMS can pull the data.
Because the PRISM does – you know, the processing is very easy for those
700-channel Napa. Every channel is, you know, less than a second.
So it all depends on how quickly AQMS is going to decide on the
magnitudes information, right, and then pull together the waveforms.
So as soon as those waveforms – you know, they’re compiled,
the PRISM is going to – kicks in and then, you know,
just generate all the – all the outcomes pretty fast.
And I believe that Chris is working closely with the CSMIP folks
to push the data automatically to their – to their website as well.
So hopefully, you know, in a couple of months,
everything will done automatically, and everything will be available on the,
you know, engineering website.
- Erol, the original networks are acquiring a lot and a great deal of strong motion
data these days as well. Are those data being processed through PRISM as well?
Well, whenever the data comes to NSMP, that’s where the PRISM,
you know, works. But if you are talking about the
other networks, yeah, they’re very welcome to use, you know, the PRISM.
I think it will nice to have some – you know, the outreach to those –
you know, the local networks to show what we have. Yeah.
- I think it would be nice for whatever products the USGS issues
to be standard and uniform. - Right.
[ Silence ]
- It’s interesting to me to hear these things going on.
Every five or 10 years or so, a group connected with strong
ground motion comes forward with bright guys and computer displays
to say – and to advertise the fact that their processing is going very well,
and people should use it. These emerging systems come from
Caltech long ago, Sacramento, USC, Ralph Archuleta at Santa Barbara.
And each has a period where the user is really intrigued
by the great steps that are – that are being taken – yours too.
In five or 10 years, when your interests change, and your followers choose
other things to do, this will fade away, and another group will emerge.
And will all of us – will all of us being paying attention to which group
that is going to be? So that’s what we’re all going to do as users of data.
I have one clarification point to make, and that is that, one of your early slides
says that the BAP procedures was written up by Converse and Brady.
It is now out of date or about to be – on the slide – I forget the phrase you used.
- Oh, we don’t say outdated. Outmoded.
- Hm? - Outmoded.
- Outmoded, yes. This is very …
- I didn’t mean to – you know, to offend.
We – actually, we used BAP a lot to start the PRISM project.
And, you know, the overall layout and then the structure – how the flow is.
So we still use, you know, a lot of things that, you know, the BAP does.
But for every software, you know, as time goes, you know, like,
the newer one comes. So right now, nobody is using
Windows 3 or 3.1, right, or the Vista or – that’s my point.
So there is this – you know, the flow of information, flow of,
you know, the new stuff. So by no means that we try to, like,
undermine the efforts that, you know, put then.
And BAP has been successfully used, you know, for the last 15 years.
- I was actually going to say that, indeed, BAP has become outmoded
with all the work that is going on and all the different inputs
that you have to attend to. But the – “outmoded” is not quite right.
The group here at the Geological Survey who was – who was preparing
data for the use by the engineering community were all offered,
back in the early ’90s, the option to get an early out from the Survey –
that is, to take – to retire gracefully.
This led to a situation where the leader of this group was left with no staff.
And for – and, I mean, I exaggerate a little, but the –
this early-out offering was followed quite closely by the
well-known rift within the Survey in 1994 and ’95.
And through some – through some procedure and for –
probably through some intrigue as well, I, as the leader, was rift.
So the Survey was left pretty much without
hands-on capability of fulfilling the BAP system.
I think that the Survey has recovered remarkably well since that time.
- Any further comments or questions?
If not, let’s thank Erol again for a nice presentation.
- Thank you. Appreciate it.
[ Applause ]
- And we’ll meet over at Tectonic – anyone who wants to join us
over in Tectonic Grill, we’ll be there in about 15 minutes.