The sounding of the first and second trumpets:
Related Commentaries of Revelation 8:7
Revelation 8:7-9
7 The first angel sounded, and there followed hail and fire mingled with blood, and they were cast upon the earth: and the third part of trees was burnt up, and all green grass was burnt up.
8 And the second angel sounded, and as it were a great mountain burning with fire was cast into the sea: and the third part of the sea became blood;
9 And the third part of the creatures which were in the sea, and had life, died; and the third part of the ships were destroyed.