Japan recently released an AI-generated video of Mount Fuji erupting, to give people an idea of what to expect if the disaster strikes and how to prepare themselves.The video shows ash spreading through Tokyo, smothering buildings and roads. Railway tracks and roadways become impossible to navigate as ash coats them. There is power outage and phones are not working. The video advises people to stock up on food for at least three days and step out wearing masks and goggles.Why has Japan released the AI video now? Is Mount Fuji close to erupting? How are volcanic eruptions predicted? We explain.Why the video nowThe video was released on August 26, which is Volcano Disaster Prevention Day in Japan, marking the setting up of the country’s first volcano observatory in 1911 on Mount Asama.Mount Fuji is in no danger of erupting soon, but it is an ‘active’ volcano, so it is capable of erupting sometime in the future. Thus, Japanese authorities periodically undertake efforts to create awareness about it.Before this, in March, the government released a report detailing measures to be taken if the volcano erupts.A volcano is basically an opening in the earth’s surface, which, through a network of vents and cracks, is connected to a store of magma, or molten rock. Due to movements beneath the earth’s crust, this magma can at times erupt out of the opening, along with pieces of rocks and steam. Once the magma is out, it is called lava.Story continues below this adThis burning lava can race down and bury nearby settlements. Ash released in a volcanic eruption can travel thousands of miles. Ash is much more difficult to clear than say snow, as it does not melt and has to be carried off somewhere else.Volcanoes which are no longer linked to a magma store are called extinct, while the others are called active, even when they have not erupted for hundreds of years. Such ‘silent’ volcanoes are called dormant, but the possibility of their eruption is not ruled out.Mount Fuji, for example, last erupted in December 1707, causing major damage in what is today Tokyo.Some experts have called the AI video “alarmist”, saying it scares people about a ‘worst case scenario’ that may not materialise, and can prevent tourists from visiting Japan. The South China Morning Post cited an expert as suggesting that the video “reflected official anxiety about being caught off guard, as happened during the 2011 Tohoku earthquake and tsunami.”Story continues below this adThere are various ways, but none is exact. Earthquakes in a volcanic region can be precursors to an eruption. Before the last eruption of Mount Fuji, its base saw earthquakes for two years.Seismic activity in the region is also studied.“Magmatic eruptions involve the rise of magma toward the surface, which normally generates detectable earthquakes. It can also deform the ground surface and cause anomalous heat flow or changes in the temperature and chemistry of the groundwater and spring waters. Steam-blast eruptions, however, can occur with little or no warning as superheated water flashes to steam,” the United States Geological Survey (USGS) says.However, since many volcanoes don’t erupt for centuries, it is difficult to adequately study and analyse eruptions. There is no saying that the situations at the time of one eruption will be repeated in the next. Also, sometimes, the symptoms can be visible for years without an eruption. According to the USGS, Italy’s Campi Flegrei volcano has been showing signs of unrest for several decades.