The Craters of the Moon National Monument and Preserve is located in Arco, Idaho and is basically a vast ocean of lava flows with an occasional island made from cinder cones and sagebrush. It was first created during 8 major eruptive time periods which were around 2,000 to 15,000 years ago. The lava first sprung from what is known as the Great Rift, which consists of a number of massively deep cracks that begin at the Visitor Center of the preserve and stretches across approximately 52 miles toward the southeast end of the park. Over time, the lava field grew, covering a grand total of 618 square miles. Smaller lava fields, called the Kings Bowl and Wapi Lava Fields, also emerged near the Great Rift around the most recent eruptive period (which was still about 2,000 years ago).
Throughout these 30 million or so years, this area has continued to stretch. For instance, in 1983, Mount Borah (which is the highest point in Idaho) grew another foot as a result of a magnitude 6.9 earthquake. As Mount Borah rose, the Lost River Valley plunged about eight feet! On the Eastern Snake River Plain, these earthquakes and other tensional forces have started a number of volcanic activities instead of creating new and majestic mountain ranges. Because of the stretching of the earth’s crust, the released pressure causes the hot rocks of the area to melt. The magma then travels to the surface and follows along the Great Rift. If (or for as long as) these geological forces sustain their progress, more eruptions are likely occur. The time in between these eruptive periods in the area of the Craters of the Moon averages about 2,000 years. However, it has been over 2,000 years since this area had an eruption, so the area is probably due for an eruption in the next few years.
You can explore the volcanic landmark by either car or by foot. Go ahead and trek through caves, craters, and remote parts of the Craters of the Moon Lava Field. The scenery is absolutely breathtaking, especially as the sun starts to go down. You’ll then be able to see a clear night sky! Since the area is designated by the International Dark Sky Park, it is guaranteed that you won’t have a shortage of stars to gaze upon.
Soon to follow are some things that you should take into account as you plan your trip to the Craters of the Moon National Monument and Preserve. There are two trails that are handicapped accessible around the park. Pets on a leash are welcome to roam around the campgrounds, parking lots, and on the paved roads. However, they are not allowed to come inside the Visitor Center or check out the NPS Monument trails unless they are a service animal. Sunscreen and a brimmed hat are recommended as well as closed-toe shoes for your personal safety. If you plan on visiting any of the caves found in the preserve, you must pick up a free cave permit at the Visitor Center before entering any of the caves. You can also pick up another permit at the Visitor Center if you wish to spend a night or two at the Craters of the Moon campground. Another permit is also required for commercial filming and photography of the park. For more information on how to obtain this permit, please contact the park.
The Visitor Center itself has some amazing exhibits, films, and advice from the park staff on how to have the best experience possible while visiting the preserve. Depending on how long you wish to stay in the park, there are a few different itineraries that you can follow (or you can just do your own thing!). If you are just stopping by for about a half an hour, you can drive around the seven-mile long loop that circles the area. If you’re there for an hour or so, you can hike up the North Crater Flow trail, Spatter Cones, and Devil’s Orchard Trails. Planning on staying for two hours? You can hike from the Spatter Cones parking lot to Big Craters and then explore Indian Tunnel (again, a free cave permit is required to enter). Thinking of spending half the day in the park? Hike up the Broken Top Loop or Tree Molds Trails and explore Buffalo Cave which can be found on Broken Top Loop. If you choose to spend the whole day or longer at the preserve, you can explore the Craters of the Moon Wilderness which includes Lava Trees and Echo Crater.
You’re probably thinking, “What is going to happen to the park if another eruption happens?” Well, taking into account the number of the past eruptions, slightly over 1 cubic mile of lava will erupt during the next eruptive period. Looking at the past, eruptions that have occurred in the Craters of the Moon Lava Field generally shifted over to the part of the Great Rift that hasn’t erupted for the longest period of time. Because of this, the next eruptive period can be expected to start along the central part of the Great Rift of the Craters of the Moon Lava Field. However, the flow could very well spread into the northern portion of the monument around the loop road. The initial flows, based on the last ones, will probably be non-explosive, whereas eruptions on the northernmost part of the Great Rift may be comparatively more explosive than the others, destroy the cinder cones, and produce some new ones in its place.
All-in-all, until the next eruptive period occurs, ongoing yet subtle changes will be happening all over the Craters of the Moon National Monument and Preserve, which means that you're safer to explore the park. The factors that will be contributing to these changes include gravity, weather, and other natural or human effects. As you come to visit this beautiful preserve, remember to keep the area clean, follow the safety guidelines, and most importantly, have fun!