1. Officials raised an alert on Thursday about an hour before the volcano erupted.

2. Until now, Mars researchers may have just been looking for the wrong kind of volcano in the area.

3. The USGS said that data they have collected indicates the volcano is still active.

4. Meanwhile, the ash from the volcano has started to make the children cough.

5. If enough lava pours out, the volcano will build a traditional cone shape on top.

6. It was the worst volcano disaster in Japan in nearly 100 years.

7. This suggests that magma is entering fractures beneath the volcano, they said.

8. The volcano has been active since 1999, with several major eruptions in that span.