Search found 830 matches

by geophix
Thu Nov 23, 2017 11:55 am
Forum: General Geophysics
Topic: Non seismic geophysics, need help!
Replies: 2
Views: 345

Re: Non seismic geophysics, need help!

I don't see many job opportunities now for mining geophysics in the U.S. But at the same time, there might not be many students looking for jobs, either. I consider it's a niche field. You still have an opportunity to find a job in the U.S. or in Canada. You can also try to find research positions i...
by geophix
Tue Oct 03, 2017 4:15 pm
Forum: Jobs and Events
Topic: choosing a research topic
Replies: 1
Views: 148

Re: choosing a research topic

May I ask why you want to get a Ph.D. in geophysics? Are you interested in seismology, exploration geophysics or engineering geophysics?
by geophix
Tue Aug 29, 2017 9:24 am
Forum: Near Surface Geophysics
Topic: Dielectric constant
Replies: 2
Views: 320

Re: Dielectric constant

Do you mind I ask why you need to measure it? It might be easiest to take a soil sample and measure it in a lab.
by geophix
Wed Aug 23, 2017 5:22 pm
Forum: Near Surface Geophysics
Topic: Awesome GPR improvement
Replies: 1
Views: 280

Re: Awesome GPR improvement

:D :D
by geophix
Sat Jul 15, 2017 8:36 am
Forum: General Geophysics
Topic: Ipi2win software geoelectrics interpretation
Replies: 2
Views: 421

Re: Ipi2win software geoelectrics interpretation

To be honest, it's hard to understand your question. I suppose for a sound data inversion program,after you input your data, the program should give you an 1D resistivity model after doing the inversion. Why are you talking about dividing depth?
by geophix
Wed Jun 28, 2017 5:20 pm
Forum: Near Surface Geophysics
Topic: US-Mexico Drug Tunnels Evolving Amid Increased Border Security
Replies: 4
Views: 405

Re: US-Mexico Drug Tunnels Evolving Amid Increased Border Security

The length of US-Mexico border is about 2000 miles. It comes down to how much money you spend per mile for tunnel detecting. The cost of GPR, ERI or other near surface geophysical surveys is normally calculated based on linear footage (or square footage), not on miles. 2000 miles is huge for geophys...
by geophix
Wed Jun 28, 2017 4:56 pm
Forum: General Geophysics
Topic: Problems with background noise
Replies: 11
Views: 788

Re: Problems with background noise

An example of Interferences from my cell phone. GSSI 270MHz antenna. If I use my cell phone, such as surfing the internet, this is what happens: interference cellphone gpr.jpg Your GPR program should be able to do Fourier Transform to do frequency analysis. Otherwise you can try the free software MA...
by geophix
Sat Jun 24, 2017 10:51 am
Forum: Near Surface Geophysics
Topic: US-Mexico Drug Tunnels Evolving Amid Increased Border Security
Replies: 4
Views: 405

Re: US-Mexico Drug Tunnels Evolving Amid Increased Border Security

It is hard to search vast areas efficiently with any methods.
by geophix
Mon Jun 19, 2017 6:36 am
Forum: General Geophysics
Topic: Problems with background noise
Replies: 11
Views: 788

Re: Problems with background noise

Maybe you can do a frequency analysis and compare the frequency bands between clear and blurry traces? I used MATGPR recently and it works good. But I am sure S&S should have similar functions. I have used S&S cart-mounted GPRs but did not use their data processing program much.
by geophix
Sun Jun 18, 2017 8:44 am
Forum: General Geophysics
Topic: Problems with background noise
Replies: 11
Views: 788

Re: Problems with background noise

Maybe you can try DC (direct current) shift removal if your data processing program has such an option? As pster mentioned, it might be interference from some electrical cables. I did see similar things before when I push a GPR over small pieces of metallic objects such as electrical wires. Did your...
by geophix
Fri Jun 16, 2017 6:16 pm
Forum: General Geophysics
Topic: Problems with background noise
Replies: 11
Views: 788

Re: Problems with background noise

In these "blurry" areas you can still see the subsurface layers. Have you tried to use some filters to filter it out? It might be low or high frequency noises.
by geophix
Fri Jun 16, 2017 11:58 am
Forum: General Geophysics
Topic: Problems with background noise
Replies: 11
Views: 788

Re: Problems with background noise

Maybe the transmitter was not working? Check the cable connection.
by geophix
Thu Jun 15, 2017 4:31 pm
Forum: General Geophysics
Topic: Dealing with magnetic data at low latitudes
Replies: 1
Views: 252

Re: Dealing with magnetic data at low latitudes

Great contents. Keep up the good work!
by geophix
Thu Jun 15, 2017 4:21 pm
Forum: Near Surface Geophysics
Topic: Magnetics on a Landfill
Replies: 1
Views: 248

Re: Magnetics on a Landfill

I would use a Proton precession magnetometer since it's more accurate (better resolution) than a fluxgate magnetometer. The precision of a Proton magnetometer is usually better than 1nT, while a fluxgate magnetometer's typical precision is around 10nT.
by geophix
Sat Jun 10, 2017 7:50 am
Forum: General Geophysics
Topic: Creating 3D ERT from 2D ERT
Replies: 10
Views: 1819

Re: Creating 3D ERT from 2D ERT

Hi, I have a similar question. I am considering affect of elevation for each electrode (topography) in 2D data sets. If it is possible to collate the 2D files with elevation in 3D format for res3d inversion program. Thanks You can collate the 2D files into 3D format first without the topography dat...
by geophix
Sat Jun 10, 2017 7:37 am
Forum: General Geophysics
Topic: Extracting EBCDIC headers from multiple segy files on a tape using segyread
Replies: 3
Views: 320

Re: Extracting EBCDIC headers from multiple segy files on a tape using segyread

I believe you can use the option shown in segyread self-document:

hfile=header

You can write a script to read multiple segy files.
by geophix
Thu Jun 08, 2017 6:13 pm
Forum: General Geophysics
Topic: GPR in clay
Replies: 6
Views: 613

Re: GPR in clay

Congrats!
by geophix
Wed Jun 07, 2017 9:08 am
Forum: General Geophysics
Topic: Mag maps in Alaska
Replies: 2
Views: 633

Mag maps in Alaska

Cool map: http://maps.dggs.alaska.gov/arcgis/rest ... geophysics
You can download them to view in Google Earth.
alaska-mag.png
alaska-mag.png (285.66 KiB) Viewed 633 times
by geophix
Mon Jun 05, 2017 7:14 pm
Forum: General Geophysics
Topic: GPR in clay
Replies: 6
Views: 613

Re: GPR in clay

Thanks a lot for quick replies:) A very complex traffic interchange will be constructed in the hard rock, approximately 10 m beneath the ground surface. The new interchange is mainly located in a hill of outcropping hard rock and the rock structures are mainly steeply dipping in this area.Can you s...
by geophix
Mon Jun 05, 2017 7:06 pm
Forum: Oil and Gas Exploration
Topic: muts and mute in seismic unix
Replies: 8
Views: 741

Re: muts and mute in seismic unix

hosseini wrote:
Sun Jun 04, 2017 6:48 pm
hi what is difference between kill and mute in seismic unix?
How can kill bad trace in seismic data?
sukill is used to kill the entire samples of the traces you select. Basically the traces are removed/killed. sumute is used to kill a portion (such as the beginning samples) of the traces.
by geophix
Sun Jun 04, 2017 9:19 am
Forum: General Geophysics
Topic: GPR in clay
Replies: 6
Views: 613

Re: GPR in clay

There is little you can do. Maybe you can try filtering to filter out high frequency components? When collecting data, lower frequency antenna would have better penetrating depth. You can also try stacking when collecting data.
by geophix
Sun Jun 04, 2017 9:15 am
Forum: General Geophysics
Topic: VLF interpretations from real and imaginary plots
Replies: 8
Views: 480

Re: VLF interpretations from real and imaginary plots

In EM (ground conductivity meter) survey, in-phase data are much less sensitive to variations of conductivities than quadrature data. Normally the in-phase data is almost flat unless there are metallic objects present.
by geophix
Sat Jun 03, 2017 12:35 pm
Forum: General Geophysics
Topic: VLF interpretations from real and imaginary plots
Replies: 8
Views: 480

Re: VLF interpretations from real and imaginary plots

I don't know whether you have the raw data before filtering. I guess the quadrature amplitude of the raw data should be relatively significant for the big anomaly. It's only after the filtering at 30m it becomes almost flat. If you have the raw data and filter it at a smaller spacing, the quadrature...
by geophix
Sat Jun 03, 2017 11:14 am
Forum: General Geophysics
Topic: VLF interpretations from real and imaginary plots
Replies: 8
Views: 480

Re: VLF interpretations from real and imaginary plots

Since the data is filtered at 30m depth, the anomalies shown in both In-phase and Quadrature (in the left portion of the plot) would indicate relatively deep hence natural conductors such as fracture zones filled with water. The big anomaly shown in In-phase but not in Quadrature (to the right of th...