What are the three hypotheses that were proposed to explain the seismic activity of Pinatubo? What process generates sulfur dioxide gas emission at a volcano?

Mt. Pinatubo is one of the contrasting volcanoes that erupted violently in the year 1991, being the second strongest volcanic eruption that took place on earth in this entire century.

The 3 hypothesis that was proposed in order to describe the seismic activity of Pinatubo includes-

The magma rising upward to the surface from the interior of the earth, erupting through the crater of the volcano. The eruption led to the releasing of a large number of volcanic gases into the atmosphere. The earthquakes are produced due to the continuous tectonic activities that are primarily caused when the earth's crust moves over the layer of viscous asthenosphere.

A large number of volcanic gases are released such as sulfur dioxide (SO₂), methane (CH₄), Hydrogen sulfide (H₂O), Carbon monoxide (CO), and other gases, due to the formation of convection currents and rising up of magma from the mantle, creating volcanic eruptions at the surface