https://geologictimepics.com/2020/03/27/touring-the-geologic-map-of-the-united-states/

What is a Geologic Map?- A Geologic map shows the distribution of materials at or near the surface of the earth.

Link to the video

How are Geologic Maps made?- Geologists measure the different features of the surface or outcrop they are surveying and then they use these measurements to make inferences on what the ground layers underneath the surface look like. When portraying the prediction of the underlayers of the area, they used what is called a cross-section. The rock types and materials are grouped into maps units and depicted using different colors. Geologists illustrate the area they are surveying and depict all the different elements they see through lines, symbols, text, and colors. They then make a key called a legend, a legend is used to describe what each of the varying lines, symbols, text, and colors mean.

https://www.researchgate.net/figure/A-The-regional-tectonic-setting-of-Borneo-and-the-location-of-significant-earthquakes_fig2_324814562

Why are geologic maps important?- Geologic maps are very useful and informative. These maps can answer many questions involving large, world issues/questions and even smaller more personal issues/questions you may have about your health or your land. For example, if you are concerned about things like Dangerous Faults on or near your property, where you can drill to get good clean drinking water for your well, what the likelihood of an earthquake in your area is, or if there are harmful contaminants in your soil causing crops to die or affecting your health, geologic maps can help to answer all of these concerns and possibly help you to find fixes for them. Geologic maps can also help to answer some of these larger concerns by proving answers that help assess and predict things like, groundwater quality, contamination risks, predicting earthquakes, volcanic activity, landslide hazards, and other natural disasters. As well as, land management and planning that help determine the best and safest places to build major highways, large buildings, etc. As you can see, Geologic maps provide a large amount of information that can be used to help minimize safety concerns.

https://www.researchgate.net/figure/Papyrus-of-TurinTopLeft-half-of-the-Turin-papyrus-mapBottom-Right-half-of-the-Turin_fig12_259753032

Some History of Geologic Maps- The oldest preserved geologic map known to date, dates back to 1150 B.C. This map portrays an accurate depiction of the topography and Geology of, Wadi Hammamat in the mountains of the Central Eastern Desert of Egypt. This amazing piece of history is now kept in the Egyptian Museum in Turin, Italy. Fast forward a little more and now we have the first geologic map in California, around 180 years ago. This map is by Lieutenant Edward Belcher, a British naval officer who created a remarkably accurate map of the Port of San Francisco in 1826, his map was published in 1839. As time goes on, people continue to make new geologic maps of different areas as well as more detailed maps of already surveyed areas. For a long period of time, paper Geologic maps were normal and in fact, the only way of producing geologic maps. That was until a group of geologists decided to play around with some GIS technology and created the first-ever digital geologic map. More time goes on and today, digital geologic maps seem to be the new normal, now you can pick from a multitude of different web options, type in a location anywhere in the work and view the geologic map of that area. You can zoom in and zoom out and do many other cool and useful things on these amazing digital maps.