Blog | Advanced Geosciences Inc

Azimuthal Method: Electrical Resistivity Methods, Part 9

Posted by Sean on Jul 08, 2019

Hello again, and welcome back to our 11-part series discussing electrode arrays. We’re deep into the non-standard electrode arrays now. This time, we’re discussing the Azimuthal Electrode Array configuration. 


In case this is your first time, we’ve also covered the following:

Part 1: The Wenner Array

Part 2: The Schlumberger Array


AGI Blog: Electrical Resistivity Methods: Azimuthal Method

Quick Tip: Improving Contact Resistance

Posted by Sean on Jun 21, 2019


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.


Gradient Array: Electrical Resistivity Methods, Part 8

Posted by Sean on Jun 18, 2019

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:

Part 1: The Wenner Array

AGI Blog - Electrical Resistivity Methods Pt8 - The Gradient Array

Quick Tip: What attracts animals to your ERI survey (and how can you stop them)?

Posted by Sean on Jun 11, 2019


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.


Square Array: Electrical Resistivity Methods, Part 7

Posted by Sean on Jun 06, 2019


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:


AGI Blog - Electrical Resistivity Methods Part 7, The Square Array

Equatorial Array: Electrical Resistivity Methods, Part 6

Posted by Sean on Jun 03, 2019


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:  

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The AGI Blog - Electrical Resistivity Methods, Part 6: The Equatorial Array

How To Do Small-Scale Electrical Resistivity Imaging Lab Tests

Posted by Sean on May 13, 2019


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...

AGI Blog - How to perform Resistivity Surveys at Scale

2019 Karst and Cave Meeting Calendar

Posted by Sean on May 03, 2019


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!


AGI Blog - 2019 Karst and Cave Meeting Calendar

Customer Spotlight: USGS | Using Resistivity to Map Permafrost Erosion on the Alaskan Coast

Posted by Sean on May 01, 2019


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.


In September...

AGI Blog - Mapping Permafrost Erosion on Alaskan Coast

Quick Tip: Depth of Investigation for ERI Surveys

Posted by Sean on Apr 15, 2019


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...