Sub bottom profiler

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Sub bottom profiler

Postby gmowoe » Thu Oct 01, 2009 8:07 pm

We are thinking to buy a sub bottom profiler for several coming projects. I googled and this company called Syqwest in on top of the Ads. It looks new. Has anyone used their products? Thanks for any information.
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Re: Sub bottom profiler

Postby timver » Fri Oct 02, 2009 7:13 am

We tried one of their products -- Stratabox. It's a horrible experience. We collected some data, and exported them to SEGY format files using their software. Then we found the sampling frequency is 15KHz while the frequency of the sound wave is supposed to be 10KHz. We called their custom service and we are told that the sampling frequency in the SEGY files could be even lower if we choose deeper depth range. Do they even know the Nyquist Theorem? How ridiculous is that?
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Re: Sub bottom profiler

Postby Gery » Fri Oct 23, 2009 3:23 pm

I've used the 4-array transducers from STRATABOX (3510) 3.5 kHz and the 10 kHz option, it's not as horrible as you may think. But yes, no good satisfactory results are obtained most of the time, I think it depends on the objective of the project. Definitely, they don't work for thin bedding surveys. Perhaps you should try with some parametric tricks, I've read something about it but haven't found any real examples.
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Re: Sub bottom profiler

Postby geophix » Fri Oct 23, 2009 6:56 pm

If I have to make a metaphor, Stratabox is like your personal car. You may like it, but don't use it as a race car in formula F1 racing. No matter how you maneuver the car in the racing, people will still laugh at you. If you are a professional marine geophysicist, don't use Stratabox. It's for amateurs.
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Re: Sub bottom profiler

Postby Gery » Mon Oct 26, 2009 11:24 am

I agree with geophix, Stratabox is not a good option. However, if you want to buy it you should work with more than 1 transducer (I think an array of 8 to 16 transducers for a "good" result). I've seen that people asking for this services, they usually look for the cheap option, this is one of them. They definitely don't want to know how this works, most of the time this science is interesting for them but not a real matter. They just want to know if the bedrock is reached, just that. For that, based on my experience, this is usually achieved by the 4-array transducer. But if you're a pro, don't even think to buy it.
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Re: Sub bottom profiler

Postby timver » Mon Oct 26, 2009 5:33 pm

OK. But I don't see how it helps by using multiply transducers. I think a transducer with better sampling frequency and software support is better than 8 or 16 lousy transducers.
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Re: Sub bottom profiler

Postby Gery » Tue Oct 27, 2009 9:45 am

In fact it helps, but first I want to state that I'm not here to defend STRATABOX!!!. Increasing the number of transducers will give a narrow acoustic beam (better directivity) in order to get good data (they use the transducers as receivers also). Obviously if you have 1000 meters below the array, the beam width foot print on the bottom will be wider, so you may start seeing unwanted artifacts in the image coming from a too wide beam. Also, this drastically reduces your vertical and lateral resolution. Now, working with a system where the transmitter and receiver work separately will be much much better. Your results are strongly dependent of the survey conditions, the seafloor morphology and sediment type (that's why I state previously that your system depends on your project's objectives).

Now about the sampling frequency, I don't know why exactly they do that, but I have some ideas:
1. Perhaps they try to put the maximum frequency bandwith in the data. Doing this, we get a 7.5 kHz bandwidth by default (Nyquist). However, in reality the maximum frequency is even less.
2. The 10 kHz transducers (monoelement) have an output signal (tone burst) with a bandwith of around 20 kHz. The 10 kHz is the resonant frequency. However, the shape of this signal is not the optimum to produce a desirable acoustic waveform.

So, if you buy it, try an array of several transducers. I don't know if they are lousy ones, but what I know it is that they can be improved (at least a bit).
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Re: Sub bottom profiler

Postby gmowoe » Tue Oct 27, 2009 2:10 pm

Points are well taken. Thanks, guys!
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Re: Sub bottom profiler

Postby geophix » Wed Oct 28, 2009 10:56 am

Grey, you made a good point about using multiple transducers/sensors. But isn’t Stratabox designed for single channel operations? Most if not all of the marine seismic systems can be operated in multi channel modes. But Stratabox, like many other subbottom profiles, is designed for single channel operation (or at most two channels with dual frequency). I think you are going to have a hell of time trying the put a series of Stratabox working together and stake the data.
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Re: Sub bottom profiler

Postby Gery » Fri Oct 30, 2009 9:45 am

Yes, it's true, that could be a horrible experience btw. We use just an array of 4 transducers interconnected by an amplifier composed of a "anti-multiples" electrical device. Perhaps someone who has been on board on a scientific ship (like JOIDES, SONNE, etc), could give some ideas about the tech aspects of putting several transducers together and getting a good data with acceptable S/N ratio. As far I know, they use other type single-channel echosounders (for other type of objectives!) like PARASOUND, TOPAS, etc; some of them work with several transducers arrays.

Now, if you are a pro, I think you have to consider buying more than one type of echosounder, may be both single-channel and multi-channel systems. Some points about the latter:
1. Boomer. PROS: Great system, strong enough for deep penetration (like 30 meters in sandy sediments) at 175 joules. In theory and in test conditions, minimum-phase output pulse. CONS: Unstable in strong swell conditions, difficults in handling both streamer and catamaran. High energy source, so potential dangerous at sea!. Expensive system.
2. Sparker. PROS: Great system, stronger than boomer. CONS: Unstable in strong swell conditions. High energy source, so potential dangerous at sea!. High costs in maintenance. Expensive system.
3. Stratabox. PROS: Quite cheap, easy to use. CONS: Ususally, "no good data" nor further processing involved (in comparison to the both systems above).

Now, you have to consider a trade-off according to your objectives, I mean, you probably won't use a multichannel system of 196 channels, 4-km streamer offset, 1400 in3 airgun source for a 20-meters water depth survey!!!

I'm not here to publish this web site!!! but I think it is a good reference with some good examples http://www.geo-resources.com/index.php?id=1022, you should give a try or surfing in google about echosounders example, there are many web sites.

Hope this helps,

Gery
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Re: Sub bottom profiler

Postby geophix » Sun Nov 01, 2009 7:54 am

Grey, looks like you are doing research/development on the sub bottom instruments. I wish I can spend some time doing this kind of stuff instead of just using them. For what it's worth, here is a list link for companies manufacturing boomers, sparkers and chirp systems including geo-resources and syquest. At the bottom of the link, there is a pdf file showing the details.

http://www.hydro-international.com/prod ... pment.html
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Re: Sub bottom profiler

Postby Gery » Mon Nov 02, 2009 10:22 am

Well, I love seismics and work mainly processing data coming from just three singlechannel systems, I don't do research but would be very interesting to do something like that. I read about it though. I use them as well for engineering projects, sometimes is a sort of boring job, but just sometimes!!! I'm learning about processing 2D multichannel seismics, and then 3D! step by step... thank you for the link, it's great.
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Re: Sub bottom profiler

Postby DELPH » Fri Nov 20, 2009 8:45 pm

Hi,

IXSEA manufactures a broad range of high quality sub-bottom profilers: ECHOES.

From low-frequency and very high power to high-frequency and very high resolution models including hull/pole mounted and towed systems, ECHOES has many built-in advantages:
- High to very high power due to specific transducer design and integration
- Flat and wide frequency spectrums allowing fully user defined chirp signatures
- Simplified and robust acquisition software
- New generation, straight-forward and powerfull processing, interpretation and mapping software: DELPH Seismic

A presentation of ECHOES technology and DELPH software can be found on our dedicated web - http://delph.ixblue.com - in the "readings" part.

Image

Best regards

Philippe
Last edited by DELPH on Tue Feb 19, 2013 7:33 pm, edited 2 times in total.
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Re: Sub bottom profiler

Postby kaden » Sat Nov 21, 2009 9:49 am

DELPH wrote:A presentation of ECHOES technology and DELPH software can be found on our dedicated web - http://delph.ixsea.com - in the "readings" part.


The reading materials are pretty good, I am impressed. Hope to see a product using parametric effect in the future.
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Re: Sub bottom profiler

Postby gmowoe » Mon Nov 23, 2009 4:58 pm

DELPH wrote:Hi,

IXSEA manufactures a broad range of high quality sub-bottom profilers: ECHOES.

From low-frequency and very high power to high-frequency and very high resolution models including hull/pole mounted and towed systems, ECHOES has many built-in advantages:
- High to very high power due to specific transducer design and integration
- Flat and wide frequency spectrums allowing fully user defined chirp signatures
- Simplified and robust acquisition software
- New generation, straight-forward and powerfull processing, interpretation and mapping software: DELPH Seismic

A presentation of ECHOES technology and DELPH software can be found on our dedicated web - http://delph.ixsea.com - in the "readings" part.

Image

Best regards

Philippe


What's the price range for these systems?
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Re: Sub bottom profiler

Postby Gery » Fri Nov 27, 2009 9:28 am

Hi Philippe, thanks for sharing these readings. I enjoyed reading the pdfs, although they are quite good and couldn't download it!, some processing stages are missed. I couldn't find a section about getting the amplitude spectrum in the frequency domain, I think an important step in post-processing to define the type and cut frequencies of each filter (i.e. notch, band-pass, etc..). Perhaps the software has that option but I didn't find it in the pdf. I point this out given some jobs in the past using boomer showed me that not all the spectrum (bandwith around 300 to 3000 Hz as it's stated in the pdf) is signal. Even though the survey was taken in a quite environment and with a low energy (100 Joules), random noise was present in the high-frequency part of the spectrum. I haven't processed chirp before (i.e. from a SEG-Y file, examining gathers in different domains, etc..), but perhaps this system is also affected in the same way as boomer for instance. So, take care with this!!!

Another thing I couldn't find is the output file from the acquisition system, is it SEG-Y rev.1? I've seen some pseudo SEG-Y files (e.g. SEG) coming out from not so good (:|) acquisition programs (again STRATABOX!!!) and ODC files, and have to admit they should be improved. I hope this is not the case.

Good job! keep it up!

Gery
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Re: Sub bottom profiler

Postby DELPH » Fri Dec 18, 2009 7:35 pm

Gery wrote:Hi Philippe, thanks for sharing these readings. I enjoyed reading the pdfs, although they are quite good and couldn't download it!, some processing stages are missed. I couldn't find a section about getting the amplitude spectrum in the frequency domain, I think an important step in post-processing to define the type and cut frequencies of each filter (i.e. notch, band-pass, etc..). Perhaps the software has that option but I didn't find it in the pdf. I point this out given some jobs in the past using boomer showed me that not all the spectrum (bandwith around 300 to 3000 Hz as it's stated in the pdf) is signal. Even though the survey was taken in a quite environment and with a low energy (100 Joules), random noise was present in the high-frequency part of the spectrum. I haven't processed chirp before (i.e. from a SEG-Y file, examining gathers in different domains, etc..), but perhaps this system is also affected in the same way as boomer for instance. So, take care with this!!!

Another thing I couldn't find is the output file from the acquisition system, is it SEG-Y rev.1? I've seen some pseudo SEG-Y files (e.g. SEG) coming out from not so good (:|) acquisition programs (again STRATABOX!!!) and ODC files, and have to admit they should be improved. I hope this is not the case.

Good job! keep it up!

Gery


Hi Gery,

We already added a frequency spectrum to the next-coming version of DELPH Seismic, which obviously is convenient to define right filtering limits. Also, we propose a range of cut-off frequencies related to the sampling frequency, making a first filter selection easier. Filtering proves to be mandatory in most cases to improve the sub-bottom imagery.

Frequency filtering is not necessary for chirp systems since it uses a chirp pulse matching filter: The correlation of the altered received pulse with the emitted signature (Frequency and Amplitude modulation) retrieves the signal reflexions only and removes extra noises that don't match de coded pulse. This has many benefits you can read in the ECHOES SBP "Advances in geophysical sensor data acquisition" presentation on the web-site (in 'readings'):
- Improved processing gain
- Higher resolution with almost perfect noise filtering
- Easier processing chain
- Envelope or real/phasis data computation
- ...

Regarding the acquisition system output, we deliver XTF or SEGY '1975' in various forms (integer/floating point precision, IBM/IEEE, etc.), rev.1 SEGY not being widely accepted yet by third party softwares (it will come ...). Our acquisition system is in use since 1989 and proves to be a standard one (ex: http://pubs.usgs.gov/of/2003/of03-402/html/segy.htm). I agree that SEGY from some third-party manufacturers are not always very 'standard', we use to deal with this for the input in the processing/interpretation software.

Thank you for the feedback !

Philippe
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Re: Sub bottom profiler

Postby Gery » Tue Feb 09, 2010 10:52 am

Hi Philippe

Thanks for your answer and sorry for my late reply. Do you have an availabe demo for the DELPH seismic software? I'm intersted in getting a copy of the "real" software because it looks like a great tool for acquisition/processing/interpretation of seismic data and very friendly!, I'd like your support about it, please send me more info to my email (e.g. cost, support, etc), gamejihou@hotmail.com.

Thanks in advance,

Gery
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Re: Sub bottom profiler

Postby sonarman » Sat Feb 27, 2010 12:59 am

Timver is probably a good marine geophysics guy.....but not so sure he understands sonar....

I have used the StrataBox and have been quite happy with its performance....

It does not store full spectrum data....it envelope detects and filters the data that is stored....therefore your comments re: Nyquist sample rate are completely wrong....and dont pertain to this product....

the instrument is primarily a device to be used for 2D visual records of seafloor sediment strata....its not designed to be a data acquisiton system....

at a price <$12,000 USD there are plenty of users whom would say they are more than satisfied as I am...

we used the product to find pockets of gravel in a quarry and saved lots of time and money in comparison to how we used to do it....

we didnt have a large budget nor a sophisticated survey platform....the StrataBox did the trick for us....

look for yourself....these images are more than satisfactory for the work we were doing...we were so satisfied we passed our results onto the company and continue to use the product on a regular basis

http://syqwestinc.com/stratabox/stratab ... pture2.JPG
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Re: Sub bottom profiler

Postby sonarman » Sat Feb 27, 2010 1:12 am

PS- You can also see in the image that the data collected by the StrataBox was post processed by Triton SB Logger....which is certainly indicative of industry SEG Y compatibility and functionality by the StrataBox

The product does the job.....which is to detect materials and sediment layers and visually represent them....it is not a data acquistion system and anyone whom bought it thinking it was probably did not do their homework....

sorry guys.....lasers cut and scissors cut..... but they are not interchangeable....
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Re: Sub bottom profiler

Postby timver » Sat Feb 27, 2010 5:18 pm

Correct me if I am wrong:

When you try to use deeper depth settings (longer trace), the instrument will automatically use lower sampling frequency, because it can only store about 400 (?, don’t remember exactly) samples for each trace. As a consequence, even you can use the zoom window, you can not get the best resolution you could get (about 6cm as they claimed) for the whole length of the trace, no matter how ideal the water or the sub bottom conditions are. I was caught in surprise since it’s against common sense. I can’t say they are lying, but it’s misleading when they say “6cm resolution with up to 40 meters bottom penetration”. You can never get both at the same time.
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Re: Sub bottom profiler

Postby DELPH » Sat Feb 27, 2010 7:49 pm

sonarman,

I agree that the use of a Stratabox is quick and 'cheap' way to achieve shallow sub-bottom mapping and get an idea of the sub-surface structure. Then, the quest for fine sediment structure for sedimentology purpose for example implies a higher resolution that can be expected from higher grade chirp systems.

An adapted power/frequency solution must be used based on sediment types and expected penetration.
A better layer definition will save a lot of time when using bottom tracking processing for picking the seabed & layers in the interpretation.

Stratbox has a 10kHz frequency, which is good for soft sediment but may be restrictive when studying harder layers (sand/gravels, ...). Their Bathy-2010 gets closer to a more polyvalent solution with a lower 3.5 kHz mode.

The given resolutions, being for a sidescan or a SBP are usually theoretical indications based on frequencies, bandwidths, chirp lengths. But the true resolution will come from the acoustic quality of both source and receiver(s) and the choice of a pulse modulation type and length resulting in a consistent resolution - vertically and along-track. Finally a key is always to be able to log raw data in SEG-Y files and use a good software for cleaning the data and increase contrasts.

The choice of a sub-bottom profiler must take all aspects into account, and it is mandatory to have a good processing and interpretation software that will get the best from the logged data, offer efficient interpretation tools and ease spatial analysis by putting all available sensor data in a geographic plane. This allows the overlay of sub-bottom profiles with other data like sonar, mag of charts for instance, so you get a much better understanding of the field you are studying. DELPH Seismic can handle all kinds of SBP data (including Stratabox SEGY) and provides such tools to perform geo-referenced processing, interpretation and visualization.

So, not only 'paper specifications' must be considered but also expected sediment types to get the right power and resolution. Also, integration, quality, maintenance aspects must be taken into account. Then any system must output at least SEGY records that can be properly and efficiently processed and interpreted with a software working on opened formats.

Regards

Philippe
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Re: Sub bottom profiler

Postby Gery » Sun Feb 28, 2010 9:20 pm

I don't expect to be sponsored by STRATABOX nor SYQWEST, but really, as Geophix pointed out before, if you're a pro you have to work with other equipment than stratabox.

Now, as sonarman pointed out, if this device gives the results a specific project is looking for, good for you, all instruments depends on the type of work you're doing, it must exist a trade-off between your objectives and the money you have to get them done. The image you suggest is quite common on what is obtained from stratabox, I've worked a long time with stratabox and seriously guys, don't buy it, there are better systems out there. You probably don't want to spend too much money, one advice, it's better to buy a better and expensive system. Now, if you want to save big bucks from big projects, buy it, clients usually don't know anything about these things, they just want the result, soft or hard, as the interpretation of the published image.

Of course! stratabox does the job, every system does the job, but it depends on the type of result you want to get from that job. This topic has 348 views, so for you guys, read forums about subbottoms like the current topic, people with strong experience like Geophix always give good advices, and look for systems specs. Check the USGS web site, they do know about surveys and systems, these guys have a strong background in shallow geophysics, it's very weird to find a stratabox there...

Ohhh!! about the SEGY, ja.. SEG is the extension format of the stratabox file (*.seg). SEG-Y is the extension for the SEG organization file (Barry et al., 1975). Perhaps I'm wrong, but they are not the same, SEG is a third-party manufacturer, usually not very standard as Phillippe pointed out.
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Re: Sub bottom profiler

Postby geophix » Tue Mar 02, 2010 7:31 pm

I don’t know whether Syqwest intentionally or accidentally make the sampling frequency this way. To me, the “optional” 3.5KHz transmitter makes more sense than the “standard” 10KHz transmitter, considering its highest sampling frequency possible is only 30KHz. You need to carefully think about your investigation depth and resolution requirements before you buy it. As sonarman said, you need to do your homework. But to be honest, this sampling frequency issue was a surprise to me, too.

Maybe they have considerations for the competition issue against their other products. But it seems unnecessary. Mala Geoscience made a cheaper version of the GPR. With this GPR, you can only download the image instead of raw data. If you want to use the raw data for post-processing, you have to upgrade it or buy a better version GPR system, with more money of course. I like this practice better since the cheaper GPR still works on a scientific basis I feel comfortable with, even I can’t download the data. I am really not sure what I can get or miss with the data without adequate sampling.
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Re: Sub bottom profiler

Postby sonarman » Tue Mar 09, 2010 9:18 pm

Timver,

spent some time studying the product before i bought it....

so more on the StrataBox....

maximum sample rate is 30 Khz...

need to select Zoom Mode to preserve this sample rate....

your assumptions about product performance are not accurate....but this is probably because you do not understand how it works....

either way there are a lot of choices out there for shallow water seismic data collection....

but there are none that sell for less than this product...

making an informed decision on a purchase is always the key to being satisfied....

some one on this thread said that you cant drive your personal car in a formula 1 race....

i say who do you know that drives in formula 1?

and therefore whom do you know that needs a formula 1 race car??

.....and the answers to both quesitons are self evident....

everyone wants to own a ferrari but nobody needs a ferrari.....

i say buy what you need and stop over paying for hype .....
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