金光明經文句記 6.107

6.107

三、正捨身，二：初、科；二、釋。經「六種震動」者，謂動、起、涌三種是形，震、吼、擊三種是聲。今於形聲略言其二，故言震動。

Third, the actual abandonment of the body, in two [parts]: first, outline; second, explanation. The sūtra's "six kinds of tremors and quakes" refers to moving, rising, and surging, which are three types of form; while shaking, roaring, and striking are three types of sound. Here, concerning form and sound, it briefly mentions two of them, and therefore says "tremors and quakes."