Understanding subsurface geology is crucial for groundwater, earthquake propagation, and ore studies. Since it’s impossible to dig everywhere and examine the rocks we record variations in their magnetic signal from the surface. The cheapest method is by walking with sensors, but it only covers small sites. Our design records data while riding a bicycle, enabling regional coverage for fewer expenses and exposure of science in practice to people of all ages and backgrounds.
Mapping of magnetic values is central to understanding the Earth’s subsurface structure. The maps assist water, oil and mineral exploration, and archaeological studies. Regional surveys are expensive, covering hundreds of square kilometers using aircraft. Ground magnetometers are used for localized site surveys only . They are limited by the range a surveyor can cover by walking while carrying the gear (about 10 KMs a day). More expensive solutions fixed the sensors to a non-magnetic cart dragged behind a vehicle and run the cart by remote control or even as autonomous systems (robot/drones). They are also localized. The adventures during such surveys are fascinating, but the stories remain hidden from the public eye, and the data is collected solely for the sake of the survey.
Our simple design scales up the coverage to thousands of square KMs, while using the same equipment and lowering the expenses. We fix the magnetometer sensor components on a polypropylene framework of pipes, anchored to an aluminum-framed hard-tail mountain bike. This provides tough endurance that maintains the sensors at a constant height above ground during the entire survey. The framework is flexible enough to absorb shocks during the off-road and single track riding. The project takes the outreach outside to meet with everyday people and stimulates their curiosity. A flash of excitement from watching science-in-action is as significant as any university classroom, maybe more. By now we covered 3300 square KMs. We met with a wide variety of people from all ages and backgrounds.
During the past 200 million years the survey region, Galilee, have seen lots of volcanism. Today some of the volcanoes are exposed, but their majority is buried below the surface. Mapping their 3D distribution is critical for accurate calculations of earthquake propagation, and hence assessing the seismic risk to the dense Galilee population. However, this distribution is unknown. Our goals are: (1) to provide the a high-resolution map of these volcanoes; (2) to prove the efficiency and low-cost of the new technique; and (3) to share the enthusiasm and joy of discovery with people of all ages and backgrounds. Instead of inviting them to our lab, we go outside. As geophysicists, the Earth is our lab.