The seven trumpets are given to seven angels. These angels are the ones that stand before the Lord. These are the seven archangels. It is another angel who brings out the golden censer. This censer is filled with the prayers of the saints. Remember from Rev. 6, the fifth seal? O Sovereign Lord, holy and true, how long before you will judge and avenge our blood on those who dwell on the earth? We are about to see what was meant by this. Rev 8-3 Another angel, who had a golden censer, came and stood at the altar.
The peals of thunder can be translated as voices. It is supernatural because it happens as a result of the censer being poured out. There is an earthquake to start these calamities and an earthquake to signal the end. The tribulation lasts three and a half years, when the world is given into the hands of Satan and the Antichrist reigns.