1)
What does this Mizmor discuss?
1.
Radak: Also this discusses the days of Mashi'ach, and the praise of Yerushalayim.
2.
Malbim: There was a great storm at the time that shattered mountains and broke rocks. The storm was also in Yerushalayim; it did not damage anything there. Hashem dwells in this mountain, and protected it. The storm benefited them. Kings of the land joined and descended in Tarshish boats to conquer Eretz Yisrael; the storm broke their boats (verse 8) and struck their troops. This is similar to Mizmor 46.
