Blog | Advanced Geosciences Inc
Honestly, this blog post has been a long time coming. Why? Because “How do I improve contact resistance?” is probably one of our top 5 most asked questions from AGI customers. The question comes up in nearly all of our AMA Webinars, seminars, and troubleshooting calls. So we’re finally answering this question in the blog (and AGI Help Desk) so that you’ll always have the answer on hand!
Alright, let’s get into it....
Today, we’re discussing the Gradient Array. Well—more accurately—the Gradient Arrays. The Gradient Array actually comes in two flavors, the Edge Gradient and the Strong Gradient. Fun fact, we recommend the Strong Gradient array the most to our customers. Why? Well, read on to find out!
By the way, this is the eighth article in our series exploring some common (and uncommon) electrode arrays.
We’ve also covered the following:
Electrical Resistivity Surveys mostly happen outdoors. Of course, you can perform small-scale tests indoors, but most clients aren’t going to give you such a comfortable project. So you’ll need to make your way outdoors into the heart of mother nature. And as such, you’ll be sharing your space with all manner of wildlife.
Some animals will shy away if they notice you working around their habitat. Others can be more curious—or attracted to some aspects of the survey.
Welcome back to our series detailing the different electrode arrays that you may come across in your work. This is the seventh article in our series exploring 11 electrode arrays and methods. We’ve covered some of the standard arrays that will cover most of your bases. In the last post, we’ve started talking about some lesser known arrays. Today, we’re discussing another non-standard electrode array—the Square Array.
If you’re interested, we’ve also covered the following:
Many moons ago we wrote a series of blog posts detailing the standard array types that you’re most likely to use in your work (links below). Now we’re back to finish off the series with the remaining 6 arrays that aren’t commonly used. And since we’re in the middle of this blog series, why not discuss the Equatorial Array? Get it? Because “equatorial” sounds like “equator”. Ok, bad jokes aside, let’s get on with it.
If you want to check out the previous arrays we’ve discussed, here are links to those posts:
In the academic world, small-scale resistivity tests come up a lot. Often, researchers need to demonstrate the theory in action. And even more often, they don’t have the space to set up a standard cable of electrodes.
With tools like the SwitchBox Grid®, researchers can create and use DIY electrode cables that are more manageable for small-scale in-class demonstrations. (Psst...we've snuck in a video explaining the SwitchBox Grid® at the end...
If you’re anything like us, cave/karst conferences tend to sneak up on you. You spend a week in May attending Hypogea in Bulgaria, and before you know it, it’s October and you’re in the USA attending the National Cave and Karst Management Symposium.
So to help you keep track, we’ve put together this definitive list of cave and karst meetings happening in 2019. Enjoy!
The USGS has done stellar work to better understand the erosion of shorelines on the U.S. Arctic coast. Two teams of scientists traveled to the very actively eroding Barter Island to collect data. Both teams observed erosion and associated shoreline loss through various means, which you can read about in full here.
This being the AGI blog though, we want to focus on the Electrical Resistivity Tomography (ERT) part of the project.
This Spanish-speaking "Ask Me Anything" webinar was hosted by Eduardo Rodrigues on 4.2.2019. Eduardo is a highly-experienced Geophysicist at our Madrid office.
There were several topics covered—all of which were generated by questions from the audience. You can link to each question using the chapters function in the video below. Want to take part in our next webinar? Sign up for webinar alerts from us so that you get an email the next time we host one for your country/time zone.
You can’t talk about Electrical Resistivity Imaging (ERI) surveys without eventually talking about depth. Aside from resolution, depth of investigation is one of the first talking points our customers want to discuss when considering ERI surveys.
What is depth dependent on in ERI?
First of all, depth of investigation will depend on the largest array span you use during your survey. Array span shouldn’t be confused with survey line length. It’s a common misconception that longer survey lines=more depth or that roll-along=more...