淺間山
Karuizawa is located in eastern Nagano Prefecture, bordered by Gunma Prefecture to the north, east and south. The town is located on an elevated plain at the foot of Mount Asama, one of Japan's most active volcanoes. The mountain is classed as a Category A active volcano. A small eruption was detected in June 2015, a more significant eruption spewing hot rocks and a plume of ash occurred in February 2015. Mt. Asama's most destructive eruption in recent recorded history took place in 1783, when over 1,000 were killed. The volcano is actively monitored by scientists and climbing close to the summit is prohibited.