Author: aredanz3

There seems to be a running trend that when we split up, disaster strikes one of the teams. (See my previous entries where each respective team got lost on two separate days)

Our splitting up today turned out to be no different, except this time, both teams encountered issues regarding the equipment. The team of three (Gabriel, Darcy, and I) planned to recover two instruments and after a breezy first recovery, we headed up to the 30-degree slope for our second recovery of the day.

Upon our arrival, we got word of a tragedy from Samer and Luis. Someone had cut one of the electrode lines in two places! And that apparently wasn’t enough for them, the culprit then stole an entire electrode! Keep in mind was fully buried! Below is a picture of an electrode.

Thankfully, these electrodes are by far the cheapest piece of equipment we put out and in fact, we have several extras as backups. For all purposes besides MT deployment, the electrodes are totally useless. Maybe the thieves needed a super ugly paperweight, but in any case, we are lucky they didn’t take any of our less disposable equipment. More importantly, a quick glance at the data suggested that the electrode was not stolen until later in the deployment, meaning we had plenty of data recorded to salvage the site.

After this news, we proceeded, as usual, to finish our recovery at the super steep site. We always make sure to check the data from the SD card before removing any of the equipment. This time it was a good thing we checked the data, or should I say lack thereof. The receiver was intended to run for 2 days—most importantly it had been running during the large magnetic storm—but did not collect a single scrap of data! We are not sure why this happened, but it may be something wrong with the receiver itself as some of the previous receiver calibrations failed on this particular instrument. This it could easily be fixed by simply replacing the malfunctioning receiver with the one we had just recovered and adding a fully charged battery. This way, all our hard work spent digging in the precarious site would not be wasted.

However, the loss of just one of our six receivers would be a major blow to productivity, thank goodness we had new team members arriving on March 2nd! One of these was Oliver Azevedo, a current Ph.D. student of the EGL lab, who conveniently had access to the four lab-owned receivers. We hatched a plan to have him carry one of the suspicious-looking metal boxes with lots of dials on it as his personal item on his international flight from Atlanta. The whole package looks somewhat like a large purse until you open it and see this strange metal box!  So long as he has no issues boarding the plane at security, this would be the solution to our newfound issue.

After swapping the receivers and re-starting the recording, we headed out to meet up with Samer and Luis for our next planned deployment of a new permanent site. We would soon be switching hotels to one on the coast, meaning our former permanent site would be too far of a drive to reach conveniently for swapping batteries (the receivers can run for about three days on two medium-sized car batteries).

The location for this site was not only perfect from a data quality perspective, but it also had the most gorgeous tree that seemed to be its own ecosystem where we were able to park the truck in the shade. (Shown below). This tree even had pitaya cacti, which in English is this known as dragon fruit, growing from some of its branches! We were also surrounded by screeching cicadas that made the site feel even more ethereal. The owners were super relaxed and came with us to the site and asked lots of questions.

Getting back on topic, this deployment was a sweaty one! The sun was beaming overhead with not a cloud in sight, we didn’t deploy in the shade because deploying too close to the big tree would mean roots in our holes. It felt muggier than it had during the past couple of days.  After such a hot and humid deployment, we decided to stop for some much-needed juice and later some fresh coconut water. This coconut water tasted even better than the last time around! The empty coconuts added to the already cluttered nature of our trusty field vehicle. We saved them to eat the inner coconut meat later that day when Samer used a machete to cut them open.

 We headed to dinner and saw this gorgeous sunset on the way!

After a much-needed swim in the pool, we called it a day!

March 1^st Progress Update:

On February 28, our seventh day of fieldwork, we planned to recover one receiver and deploy two, one of which was almost on the beach. A beach excursion was sure to ensue.

Our first site of the day was scouted but we had not yet obtained permission from the landowner to deploy. Seeing that we were unable to obtain permission we decided it would be better to look around for an alternative location where permission might be easier to find.

Lucky for us, the answer to our problems was right across the street at a chicken farm. We quickly got permission from the kind owner and Samer and Darcy made the trek up a large hill behind the property to scout around for a good location.

Not only did they have chickens at this farm, but there was also a litter of the most adorable puppies for me, Luis, and Gabriel to hang out with as we waited for the green light from Samer and Darcy. In addition to this, upstairs in the bathroom was the cutest litter of kittens. This was the most amazing waiting around we had done thus far.

This quickly came to an end as we realized we would be unable to drive the truck up the large hill, meaning we would all have to work together to carry the heavy equipment and tools needed for deployment up said large hill. This deployment was closer to powerlines than is usually ideal, but we made do. After some grueling work and a lot of loud shouting due to the fact that we left our walkie-talkies in the car, we wrapped up and headed out, stopping to say our farewells to the animals on the way.

We quickly moved on to our recovery which was done in 15 minutes or less at the site with our old friend the stubborn bull (shown below posing for the camera).

After this, we did some driving down to the coast for our next deployment. The site was in yet another black and charred field, if you can’t tell by now, it’s defiantly dry season in Costa Rica. The beach was within reach at this deployment, just barely visible over a small hill.

We have met a variety of cows on our journeys, some wanting nothing to do with us and some being a little too obsessive. These particular cows were friendly and came to greet us, we hope that our kindness may deter them from eating our electrode cables. This may sound insane but it’s a genuine issue.

With our hopes high from Samer’s promise of a beach visit before heading inland back to the hotel, we blew through the deployment in around 50 minutes (record time!!!)

We had a small battery hiccup, but Samer and Darcy used their expert skills to diagnose and fix the issue before we headed out to the beach! You cannot imagine my excitement! We ate watermelon to celebrate and then explored the beach.

Samer when into national geographic photographer mode. Shown below are some of his portfolio from the day.

I found some super cool and amazing shells! This was the best end to a super successful day! We headed to the hotel to pack up and move to a new hotel with a pool. We arrived at our new hotel to learn they had canceled our reservation! Our dreams of the pool were shattered! We thankfully found lodging in a hotel down the road which had a pool! Our dreams of a pool were restored. We finished off this amazing day with a swim in the pool.

After a day of working together, we decided to try splitting up again for our fifth day of the campaign (February 26). We used the same groups. These groups are mainly dictated by who can and who can’t speak Spanish: Luis being fluent in both, Darcy being semi-conversational in Spanish and Gabriel being only fluent in Spanish. Samer and I cannot speak Spanish very well. Samer and Luis went off to check on the permanent site and recover two sites to the north. The deployment group—which was made up of Darcy, Gabriel and I—set out to do just that: deploy a site about 20 minutes south of our hotel.

The location where we were going to deploy was gorgeous and shaded with some of the easiest digging we’ve seen so far this trip. Even though it was only three of us, we blew through the easy installation in less than an hour. We made such great time, I even had time to find and eat a mango fresh off the tree. We left and headed back to the hotel to relax and wait to meet up with the recovery team for the second deployment.

While things were going easy breezy for us, we soon found out this was not the case for Samer and Luis. We received a phone call from Luis and Samer expecting to hear news of a successful recovery and hoped they would be returning soon to start the next deployment. This was not the case.

They had (somehow!) accidentally driven all the way to Liberia, a large city with an airport about an hour east of their intended destination. This was yet another lesson in not trusting Google Maps.

The deployment team decided that only one hour of work for the day was not sufficient while Samer and Luis were still recovering far away sites and getting lost. We would have installed another site, but we needed the equipment that was being recovered by Samer and Luis in order to complete one. So instead, we headed out to scope out the site we had intended to deploy that afternoon to make it easier to deploy first thing in the morning of the next day. This planned site was up into the mountains south of our hotel which was different than all the previous sites installed on the flat farmland to the north. We climbed up and up and up on steep, windy, and extremely bumpy roads. After some difficulty, we eventually found the landowner for the site that Carlos had scouted. The landowner hopped into our truck to take us to the site location. After a little deliberating, Darcy, Gabriel, and I found a—what some might call—”less than ideal location”. Luis and Samer made it back safely after a longer-than-expected excursion to recover the two receivers and we all met up for dinner.

February 26th progress update:

The next day, on February 27, all five of us returned to this site to install it. At this point, I’m sure you’re wondering what I meant when I titled this post because things seem to be going relatively okay. By things are going downhill I meant that our East electrode had to be installed on a 30-degree downhill slope at 9 am. What a start to the day. Pictured is Samer’s face when he realized this is the site that we had selected the previous day when scouting

Although not ideal, MT can be done on steep slopes like the one we selected; it may lead to some strange behavior of the electric fields that can be addressed in later processing and modeling steps. Normally we would prefer something less hazardous, but in this case, the landowner who gave us permission to deploy on his land had only two potential site locations. Our options were an easy deployment essentially boxed in on all sides by noise sources (three powerlines and a cell tower that requires large amounts of power to run), or a difficult deployment with little to no noise. Good data supersedes danger, so the 30-degree steep slope was our poison of choice! Plus, it had the most gorgeous view! And because of the higher elevation, the temperature was surprisingly cool instead of the scorching >95°F (35°C) temperatures in the lower pastures.

After this treacherous deployment we powered through another deployment in yet another unmemorable pasture (are you seeing a trend here yet?). While this was an ordinary deployment for everyone else, this was an exciting deployment for me because I got to calibrate and program the MT receiver to collect data for the first time!

February 27th progress update:

On our fourth day of fieldwork (February 25), we had ourselves a mouthful of a plan. We would drive a two or three-hour total loop up to the northwest coast stopping around every 30 minutes to either deploy or recover a site. We hit the ground running with a deployment in a pasture that looked just like every past pasture we had deployed in; they all blend together rather quickly. What makes this one distinct was that Samer and Gabriel took it upon themselves to become cattle herders. But not just any cattle, but a very large bull that refused to leave our designated deployment area. Samer grabbed a stick and started hooting and hollering at it. Shockingly, this strategy was successful, and no one was injured.

This was our only hiccup and after a successful deployment (where I dug a very cute magnetometer hole) we quickly moved on to recover a site we deployed in another pasture 2 days prior.

Unfortunately, this recovery was not as expected. The batteries we are using are supposed to last for 40 hours ideally, meaning plenty of time to record data that can penetrate deep into the ground. However, the battery at this site supplied power for just around 18 hours before dying, meaning the batteries are not working as they should for some reason. Fortunately, this is an easy fix since we can just use two batteries connected together rather than one battery for all future sites. Thankfully, the site was in a quiet location and so even with the shorter run time, the data ended up looking quite good so we decided to recover the site anyway.

Fruit seems to grow everywhere in Costa Rica: oranges, mangoes, bananas, star fruit, guavas, and more! We spotted some fresh cashew fruit (shown below) en route to the next site. This was my first time trying cashew fruit! It was good but very astringent or tart. I also learned that raw cashew nuts fresh off the tree contain urushiol which is a toxic resin that can cause skin irritation. The actual cashew nut part is encased in a very tough shell making it almost impossible to eat. Regardless, it was good to know.

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Our next planned deployment was supposed to be on the land of a tourist resort on the very northern end of the Nicoya Peninsula. This plan went up in flames, literally. The resort was in the middle of dealing with a large wildfire. After almost losing some toes to a very large firetruck, we decided moving on to another nearby location would be our best course of action. The “nearby location” was un-scouted because our incredibly helpful and life-saving field coordinator, Carlos Ramírez, had driven all over the peninsula already and scouted pretty much everything else on the whole peninsula except this point. We did not mind having to scout at all given that Carlos is the biggest reason this fieldwork campaign has progressed so efficiently thus far. Scouting meant that we would have to find a spot to put the instrument ourselves, essentially meaning we drive around and knock on people’s doors to ask them if they have land they would be willing to let us use for two days for earthquake research. After only two dead ends, we stumbled across a man leading a group of men on what seemed to be a tour of his land. A short conversation later and we were on our way to deploy in a shaded horse pasture.

In our excitement of finding a site, we managed to get neither the landowner’s name nor his number, meaning we had no way to contact him about potentially moving the horses in the pasture we selected. When we deploy in farmlands, animals tripping or eating our cables is always a concern. If a cable is eaten or disconnected, our recording is cut short which is not ideal given the time and effort we put into deployments. Luckily these horses did not seem like the type to have a palette for wires.

I found two semi-ripe mangos (very exciting), pet some horses, and also saw some bats in a creepy well. This was a quick and easy deployment located only a mile at most from the beach.

Samer said we could not go to the beach. We then headed to our last task of recovering a site, which exhibited the same battery issue we saw at the first recovery of the day, and then make the drive home for some much-needed dinner.

February 25th progress update:

On our third day of fieldwork (February 24, 2023), we planned to install one site and pick up our first deployment. Our installment of the day was in a sugar cane field owned by a large company called CATSA. The farm was a major industrial operation and after a security check, we were guided to our site location, passing endless fields of sugarcane. The field where we would install our site had recently been burned to remove the debris left after the recent harvest, so it looked very post-apocalyptic and smelled like burnt molasses. The ground was covered in dark ash and the wind was howling with a vengeance, meaning we were all completely covered in soot. We quickly got to work!

An MT deployment consists of deploying 4 electrodes to sense the electric field and 2 magnetometers to sense the magnetic field these components connect to the central console which is the actual MT receiver. To start off our deployment, Darcy usually orients us and we begin walking out the electrode lines.

We deploy the electrodes like a compass, one in each direction, north, south, east, and west. The electric field is measured in both the north/south and east/west direction. In order to do this, we lay out a cable that connects the receiver to the electrode. This is usually around 50 meters on all 4 sides. This creates a 100 meter spread between the north-south electrode pair and the east-west pair.

These electrodes (shown in the diagram above in red) must be buried and kept moist to ensure an optimal reading of the electric field. To keep them damp we use clay-rich kitty litter that we put in reusable bags. and add water to each hole. The clay in it works well to retain the water and keep the electrodes damp for the duration of recording even in super dry and hot areas (like Nicoya!).

The magnetometers (shown in the diagram in blue as induction coils) must also be buried (the locations shown in diagram). These must be level with one pointing in the east-west orientation and the other north-south to record the magnetic field signal.

Once the electrodes and magnetometers are buried, its just a matter of hooking up the battery to the receiver and calibrating the receiver. The last step is to press start on the recording after we program the receiver to record data! And that’s it!

For this site, we used rocks to hold down the cables to decrease wind noise in the data and, despite the windy conditions, successfully deployed our fifth MT site of the field campaign.

As I detailed in my last update, we had been taking the first few days at a slower pace and working with all 5 of us together. But now that everyone was getting the hang of the workflow, we decided to split up after our first deployment at the sugar cane field so that one team could go check the battery level at the permanent site and the other team would go recover our first deployment site.

This seemed like a great idea until the recovery team (Darcy, Anna, and Gabriel) immediately got lost. We spent around 20 minutes driving in circles on some extremely bumpy dirt roads before locating our actual deployment site. We had taken the wrong dirt road and none of us even realized! Without the homeowner and his dog as our guides we were hopeless. Yes, we did have an exact GPS point of the location but after you drive down like 5 dirt roads, they all start to blend together. Google Maps is not the most reliable on rural dirt roads in Costa Rica and we learned that the hard way, when it lead us into a dead end of bushes and told us to keep driving. After finally locating the site—which was actually down a completely different network of dirt roads than the one we falsely remembered it being on—we quickly recovered the site. Recovery takes significantly less time than deployment because you only remove items from holes rather than dig the holes.  Funny enough, we spent less time recovering the site than we spent driving around to find it!

This was our first recovery, meaning it was our first chance to see if all our hard work was worth anything. The moment of truth. The instrument was still running when we arrived. That’s a good first sign. After doing a quick QC of the data, they looked a bit noisier than we expected (perhaps due to shorter electrode lines constrained by a relatively small fenced area), but still completely useable. We have collected usable data! This is always a big relief at the start of any field campaign after all the planning and preparation (and hard work digging!).  

February 24th progress update:

Hey guys, welcome back! This time I’m back with a bit of a more behind-the-scenes science-oriented blog post, but bear with me through it cause it’s actually super exciting. This will help you gain an understanding of what it is that we are recording with our receivers. Even if you just skim this article (which is totally okay! Any attempt to expose yourself to science is great in my book!) it will hopefully help at least a little with your understanding of what we are trying to do.

When you hear the terms “electric field” or “magnetic field”, it’s easy to mistakenly think of them as completely separate things. In reality, they are essentially two sides of the same coin: electromagnetic fields. When you have a magnetic field that varies with time, it generates an electric field that can induce electric currents in conductors (this is how an alternator in a car works to keep the car battery charged while we drive, and also how generators at powerplants work to produce electricity). The same holds in reverse: a changing electric field generates a magnetic field. This means that one creates the other and vice versa in an unending cycle that we call “electromagnetic waves” (also known as “light”). Similarly, when an electric current is flowing in a conductor, it also generates a magnetic field. For example, if you were to place a compass near an electric wire, the needle would be deflected by the motion of electricity through the cable. This relationship between electricity and magnetism is how we end up with the phrase electromagnetism. Basic electromagnetic principles are fundamental to a huge amount of our modern society including power generation, WiFi signals, cell phone transmission, etc. 

On Earth, electromagnetic principles also drive important geophysical phenomena. For example, deep inside the Earth, there is a liquid outer core where molten iron (a highly conductive fluid) experiences convection. The convecting molten iron is essentially a moving electric current which then generates  Earth’s magnetic field. This is often represented as a huge bar magnet through the center of Earth with a geomagnetic field that surrounds our planet.

This geomagnetic field allows us to navigate with a compass and also protects the atmosphere from essentially being blown away by the gusts of charged particles that the sun is constantly emitting, which is called the “solar wind.” It also protects us from being bombarded by harmful electromagnetic radiation, which is very, very, very bad for living organisms, including us humans.

As it just so happens, at this very moment (February 27^th) we are in the midst of a large “geomagnetic storm”. This means our geomagnetic field is currently being pushed by a stronger-than-usual solar wind force, thanks to a solar flare from a sunspot. A beautiful side effect of this will be an increase in auroras, because of the strength of this storm they will be visible farther south than usual, including in the northern portions of the continental United States.

Why is this important for our method?

So, given all the above, let’s put this all together to explain what we are measuring on the Nicoya Peninsula using the magnetotelluric method. When the solar wind (i.e. a stream of charged particles) pushes against our geomagnetic field, it changes the geomagnetic field by a tiny amount, and—as  I mentioned earlier—a changing magnetic field creates an electric field! Electric fields create magnetic fields create electric fields everywhere!

So what does that mean for us and the instruments we have collecting MT data right now?

Well as it turns out, the time-varying geomagnetic field is the very source of energy that powers the magnetotelluric (MT) method! This energy source can induce electric currents, in the same way that we can charge our smartphones without connecting them to a physical cable. However, since the ground is relatively conductive while the atmosphere is highly resistive, no current is induced in the air, only in the ground beneath our feet. No matter where you are, there are always extremely weak currents flowing beneath your feet!

Our MT instruments record the naturally occurring electric and magnetic fields over time. By measuring these fields, we can create an image of the electrical conductivity structure below the surface and how it varies spatially and with depth because electrical currents preferentially flow through conductors. The larger the perturbations to the geomagnetic field, the more signal we have and the easier it is to constrain the conductivity structure. Therefore, geomagnetic storms are a good thing for MT, since it provides us with a massive signal boost that improves the quality of our data. This helps us to get more information out of the data to peer deeper inside Earth.

Samer and I arrived in San José, Costa Rica on February 19^th. After picking up our 11 comically large and heavy cases of geophysical equipment (pictured below) from the airport, we headed to grab the rental car.

The first day of our stay was spent sorting out logistics while staying at the most gorgeous hotel, Gran Casa Universitario. The project co-lead, Darcy Cordell, arrived the day after and once we secured a second rental car, we began preparing to head out to our study area, the Nicoya Peninsula. Along the way, we also secured the generous help of two Costa Rican locals. The first is a geology student at the University of Costa Rica, Luis Salas, and the second is the muscle of our team, Gabriel León. We all made the four-hour journey to our destination of Santa Cruz, Costa Rica, which is centrally located on the Nicoya Peninsula. After a day to settle in, we set out to start deploying MT receivers.

We were lucky enough to have an amazing project collaborator, Carlos Ramírez, who scouted the sites for our MT deployments so that we could save time in the field (thank you, Carlos!). The ideal site for collecting MT data should be far from any large electrical signals since these saturate the highly sensitive electric and magnetic sensors and create too much “noise” in the data. Common sources of noise include powerlines, electric fences, pipelines, ground vibrations (such as being close to a highway), the passage of vehicles (basically large hunks of moving iron), and electric trains. The presence of a noise source obscures the natural electromagnetic field signals (in a future post I will go into more detail about where this signal originates)  and thus makes it almost impossible for us to image the subsurface. Lucky enough for us, Costa Rica is not a densely populated region which means fewer power lines and more potential sites.

We set out for our first deployment on February 22^nd  and thanks to Carlos’s scouting, we ended up with an amazing site nestled in a remote farmland. We spent around two hours on the first deployment, allowing plenty of time for everyone on the team to become familiar with the workflow of MT deployment. After a twenty-minute test run of the receiver, the preliminary data recorded looked promising, meaning low noise interference.

After this, we quickly moved on to our next deployment, where we were met with a long string of gated farmland. After making it through the multiple pasture gates, we encountered a few setbacks involving cows, wasp stings, and accidental trespassing. Once these were resolved, we settled on a site located near the far end of the farm.

After our breezy and spoiled experience at the first site of the day, this site proved to be not only a huge tripping hazard due to large holes and cracks in the dry ground but also made for very difficult digging in the rock-solid dry soil.

This site is intended to be a longer-term deployment, meaning we will leave the site out to collect data for around a week rather than two to three days. Even after all our issues, we did manage to have a successful deployment with no further hiccups. This was celebrated with juice boxes before heading out for the day.

February 22nd progress update:

Our second day of deployments had similar success! The first site was also located on a cattle farm, and we were met by lots of parrots, a starfruit tree, and a genuine cowboy on horseback who pointed us to where our next site would be. While this site was closer to powerlines than our two sites from the first day, it was still located far enough away to avoid overpowering the natural signal. The second site of the day was similar to the first and went even quicker, setting a new record deployment time for this trip of only one and a half hours from start to finish! The end of this day was celebrated with fresh coconut water from a roadside stop. These two days of mostly smooth deployments are encouraging as our goal is to deploy a total of 40+ MT sites before our fieldwork ends on March 20th.

February 23rd progress update:

Hola! Welcome to the first installation of the Nicoya-MT blog, posted by me, Anna Redanz everyone’s favorite research assistant in the Electromagnetic Geophysics Lab (EGL) lab at Georgia Tech (there is only one, so I win by de-fault). This first post will serve as an introduction to the objectives of the project that will be running for the next month on the Nicoya Peninsula in Costa Rica.

The highlighted light blue line off the coast is a subduction zone where two tectonic plates are colliding; this one is the Middle America Trench! The denser of the two plates, the Cocos Plate, is pulled under the Caribbean Plate which creates subduction. Our study area is the Nicoya Peninsula, denoted by the pin. At this location, the distance to the trench is notably shorter than is typical, as indicated by the distances shown from El Salvador(pink line) and Guatemala(orange line). This makes this region peculiar as the land is located above the shallower portion of the subduction zone.

Subduction zones, being a plate boundary, allow for massive amounts of stress buildup to occur at the plate interface. This interface forms a large fault zone, known as the megathrust, which is where the Cocos and Caribbean plates are in contact with one another. At a typical subduction zone, the buildup of stress is eventually released as large, often destructive earthquakes. The section of the subduction zone that encompasses the Nicoya Peninsula experiences such earthquakes, the most recent being a magnitude M7.6 event in 2012. However, what makes this region particularly interesting is that it also experiences “silent” earthquakes in the form of slow slip events (SSEs), where the stress release occurs over longer periods of time lasting days to weeks. These SSEs are undetectable to those living in the area since they do not cause ground shaking like normal earthquakes, but scientists can detect them using GPS stations that track the movement of the plates. Why do some portions of the Nicoya Peninsula experience SSEs while others have destructive earthquakes? Scientists have proposed several hypotheses, but we don’t yet know the exact reason why. This is one of the questions we aim to answer through the data we collect on the Nicoya peninsula.

How exactly do we plan to study something located far beneath the ground? For this, we will be using an electromagnetic geophysics method called Magnetotellurics (magneto-tell-er-ics), or MT for short. The MT method records very small changes in the Earth’s magnetic field and the (very) small electric currents flowing in the ground that are generated by the changing magnetic field. By recording how well electric current travels through the subsurface, we can get measurements of how conductive or resistive the underground structures located far beneath our feet are. Being able to see how the conductivity changes can help us create a picture of what is happening at the subduction zone and what might be present.

The oceanic plate (that has been underwater for millions of years and is wet or ‘hydrated’) is being pulled down into the hot mantle, meaning that this water-rich crust is now entering the subsurface. We know water is very conductive (it carries electric current easily) and the MT method we are using to “see” into the earth is sensitive to changes in conductivity, this means by using MT we can image the movement of fluids in and around the subduction zone. We want to know how these fluids affect the mechanics of stress build-up at the subduction zone, which lead to the creation of earthquakes and may have an influence on the slow slip events that I mentioned earlier.

In order to investigate our hypothesis, we have to go out and collect MT data in our study area. This will be done over the next month as we travel around the Nicoya peninsula to dig a bunch of holes and trenches and deploy as many MT receivers as time allows. I’ll be updating y’all as our journey progresses!