A person describing being on a hill during a major earthquake told me he could see the surface of the earth moving like ocean waves. This seems to fit the description in Psalm 114.
When Israel went forth from Egypt,... mountains skipped like rams, hills like sheep. (Psalm 114:1,4, JPS1985)
The description in Exodus is:
Now Mount Sinai was all in smoke, for the LORD had come down upon it in fire; the smoke rose like the smoke of a kiln, and the whole mountain trembled violently. (Exodus 19:18, JPS1985)
Undoubtably the language in Psalm 114:4 is poetic, but what is it expressing? It isn't expressing joy.
Tremble, O earth, at the presence of the LORD, at the presence of the God of Jacob, who turned the rock into a pool of water, the flinty rock into a fountain. (Psalm 114:7–8, JPS1985)
Psalm 114 apparently expresses more than the parting of the sea. It even mentions the Jordan in v3. Basically Psalm 114 can point to evens from the parting of the sea leaving Egypt until Israel crossed the Jordan river. Water from the rocks also occurred at that time. Thus, reference to mountains would seem to point to Sinai.
חוּל S2342, 2343 TWOT623, 624 GK2565, 2566 [חִיל S2342, 2427 TWOT623, 623b GK2655, 2656, 2659] vb. whirl, dance, writhe (NH, Aramaic id., dance; Arabic حَاَل (ḥaʾal) change, turn; Assyrian ḫîlu, writhe in fear Dl 191 (on ḫ = ح (ḥ) v. DHM i. 357); on form of Heb. vb. v. Nö, 1883, 536) -- Brown, F., Driver, S. R., & Briggs, C. A. (1977). In Enhanced Brown-Driver-Briggs Hebrew and English Lexicon (p. 296). Clarendon Press.
Figure 1. Senses of חיל/חוּל as used in the Tanakh (generated by Logos Bible Software)
I חיל and → חול: MHb. except אחילו shivering fit only חיל to be in labour 1QH 3, 8; Ug. ḫl, Ph. DISO 87, Akk. ḫiʾālu Arm. lw. vSoden Orient. 35:11, → Scharbert 21ff. -- Koehler, L., Baumgartner, W., Richardson, M. E. J., & Stamm, J. J. (1994–2000). In The Hebrew and Aramaic lexicon of the Old Testament (electronic ed., p. 310). E.J. Brill.