Volcanic lakes like Lake Nyos can explode, releasing deadly gas. Scientists studied sediment from lakes in Europe and Africa to find evidence of past gas bursts. They found markers like unusual sediment colors, gas-rich layers, and changes in chemistry. By dating these sediments, they learned when these events happened and how often they occur. This helps us understand the risks of similar explosions in other lakes. Lake Monoun in Cameroon is a good place to study because it's smaller and easier to access.