וַיְהִי֙ כְּכַלֹּת֔וֹ לְדַבֵּ֕ר אֵ֥ת כָּל־הַדְּבָרִ֖ים הָאֵ֑לֶּה וַתִּבָּקַ֥ע הָאֲדָמָ֖ה אֲשֶׁ֥ר תַּחְתֵּיהֶֽם׃
And it came to pass, as he made an end of speaking all these words, that the ground did cleave asunder that was under them.
Read kabbalistic (mystical) interpretation of Numbers 16:31: and classical mystical sources.