The long-running series in which readers answer other readers’ questions takes a deep dive into the unknown and untrodden ...

Japan’s largest volcano lies hidden. It can be found, if you know where to look, by starting from the southern island of Kyushu. Find the active volcano Sakurajima. (We will come back to it later.

Mud volcanoes are often pictured as dramatic geological phenomena featuring the sudden eruption of large volumes of fiery mud ...