Uturunco is a stratovolcano in Bolivia that has not erupted for about 250,000 years and is considered dormant/extinct.

However, despite its classification, it has been showing signs of life since the 1990s. Ground deformation with hallmark subsidence and uplift patterns, and elevated seismic activity are not typically associated with inactive volcanoes. It has caused some speculation that it could erupt in the future. 

A multinational research team performed an investigation both because its a really interesting case of a long dead volcano showing life but also because if it did manage to erupt, it presents significant danger up to supervolcano and caldera forming eruptions. Their findings indicate the volcano is not an imminent threat. The deformation and earthquakes are attributed to hydrothermal and gas accumulation.

In other words, this volcano is indeed alive, after a very long nap. Those signs themselves indicate that. Yes, it may be hydrothermal and gas, but where do those features get their origin? There's magma in there somewhere, but its not close to the surface at this time. Hence the word no sign of imminent eruption.

However, this does not diminish it's significance. Things can change quickly and its a remarkable case. It appears that sometime around the 1990s,  a volcano dormant for 250K years rumbled to life. It may never get to eruption, or it might eventually. Regardless, things aren't necessarily what they seem beneath our feet. We are watching new hydrothermal features emerge and volcanic creep higher. Many haven't progressed to anything major yet, but they certainly could. Santorini, Campi Flegrei, Iceland, and a number of places are of interest at this moment. Just like they were in previous ages and historical times. 

We watch the volcanoes. Not just for the danger they pose and direct influence on the environment but also because they give us an idea of whats going on beneath our feet. We continue to find out that the solid earth is changing as much as anything else. Its dynamic. While this "zombie volcano" doesn't appear to pose an imminent threat, it is alive, and will be monitored as such. Warning signs would be if seismic activity, fumarole emission, and/or deformation were to change..

Scientists solve mystery of 'zombie' volcano displaying signs of eruption for decades