Fire Upon Italy: The Bologna And Genoa Incidents

The Italian Government changes and so does its policy. The ceasing of immigration flow through Italy is one of the top agenda, and Italy rose its voice in Europe on several other issues. During this period of change, or desired change, Italy is stricken by two "incidents" within the space of eight days.

On August 6 a tanker truck loaded with GPL doesn't see that the lane is stuck and impact the truck in front, exploding (see the Video). The media speak of a "chain of explosions" but the available footage show the first explosion and what they called  "the last one", a hug blast which was capable of opening a crater in the highway overpass.

Between the two explosions, however, there seem to be some discrepancies in the surrounding landscape as well as in the traffic flow. In the second video there are no cars except one (a white compact vehicle with smoked glass and possibly without a plate?)

The extent of the second explosion seems to not match with the presence of the tanker truck (which had already exploded) and some trucks. It doesn't sound probable either that one or even two explosions on the road could have caused a crater underneath, unless the blast came from under the highway level. In that case, what was it?