Q. See question above. Does one say a bracha when experiencing a killer or damaging large earthquake?
A. Shulchan Aruch (O.H. 227: 1) rules that on earthquakes as well as lightening and thunder, or on very strong winds
storms one recites the brocho of “Oise Maase Bereshis.” However, if he desires he may say; “Shekocho, Ugevuroso Ma’ale Oloim. His force and strength fulfills the universe.”
Although it may seem strange to bless Hashem for something that is usually destructive and harmful, however, the blessing is obviously recited by the ones that were saved and survived.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit'a