It was just reported that a 5.2 magnitude earthquake occurred in Kagoshima, Japan. The earthquake happened directly on top of the Sakurajima supervolcano caldera lid.
https://earthquake.usgs.gov/earthquakes/eventpage/us100098pn#executive
This represents the type of earthquake that has the highest potential of causing a catastrophic eruption. Should such an earthquake sufficiently weaken the lid covering the caldera, the lid would fissure and break, resulting in a deadly eruption. We argue that such an event would represent the manifestation of the opening of the Sixth Seal.
The opening of the Sixth Seal is the next event on the timeline of Revelation.