Matsya Purana — Intermediate Dissolution
अग्निप्रस्वेदसम्भूताः प्लावयिष्यन्ति मेदिनीम् समुद्राः क्षोभमागत्य चैकत्वेन व्यवस्थिताः //
agniprasvedasambhūtāḥ plāvayiṣyanti medinīm samudrāḥ kṣobhamāgatya caikatvena vyavasthitāḥ //
Born from the fiery perspiration of the cosmic heat, the oceans—rising in agitation—will inundate the earth; and, having surged together, will stand as one single expanse.
It describes a key Pralaya mechanism: intense cosmic heat generates “fiery perspiration,” from which the oceans become violently stirred and merge into a single mass of waters that inundates the earth.
Indirectly, it frames the ethical urgency behind Manu’s preparedness: rulers and householders should practice dharma, foresight, and disciplined stewardship, knowing worldly stability can be overwhelmed by cosmic cycles beyond human control.
No direct Vastu or ritual rule is stated; the takeaway is environmental totality—during Pralaya all terrestrial boundaries are erased—an idea later used in Purāṇic thought to stress choosing elevated, stable sites and performing rites with awareness of cosmic cycles.