Is there a blessing over an earthquake?

Hello, 

1. There is a blessing over an earthquake. 

The blessing is: 

ברוך אתה ה' אלוקינו מלך העולם עושה מעשה בראשית. 

Or, if he wishes, he may instead recite:

ברוך אתה ה' אלוקינו מלך העולם שכוחו וגבורתו מלא עולם 

(Shulchan Aruch, Orach Chaim, siman 227, seif 1). 

2. One must recite a blessing for every earthquake, even if it was not a large earthquake that endangered human life, but rather whenever it is clear to him that he felt an earthquake, he recites a blessing (Shu"t Shevet HaKehati, vol. 5, siman 46, and cited in Chazon Ovadia, Berachot, p. 461. This is unlike what was written by HaGaon R. I. Weingarten shlit"a in the collection Or Yisrael, Adar 5763, pp. 52-56. See what was answered to his words in Sefer Shaar HaAyin, chapter 6, note 3). 

3. One must recite the blessing until the time span of tokh kedei dibbur after the end of the earthquake, but after this time has passed, the blessing can no longer be recited (Olat Tamid and Eliyah Rabbah, end of siman 227, in the name of Birkat Avraham. So too in Birkat HaBayit, gate 30, seif 1, and in Chazon Ovadia there). 

4. If some time has passed since the earthquake and he has diverted his mind from it, and then another earthquake occurs, he should recite the blessing again even within thirty days (Birkei Yosef, siman 227, letter 6, in the name of Maharam ben Chaviv in a responsum. And in Sefer Chut Shani, Shabbat, part 3, p. 229, it is written that it is reasonable that even on the same day one should recite the blessing again over an earthquake, unless they continue one after another, in which case one blessing is sufficient). 

With blessing, 

Hillel Meirs