Matsya Purana — The Slaying of Jambha and the Rise of Tāraka: Divine Battle Formations
ततो वज्रास्त्रम् अकरोत् सहस्राक्षः पुरंदरः तदोपलमहावर्षं व्यशीर्यत समन्ततः //
tato vajrāstram akarot sahasrākṣaḥ puraṃdaraḥ tadopalamahāvarṣaṃ vyaśīryata samantataḥ //
Then Sahasrākṣa (Indra), Purandara the city-destroyer, discharged the Vajra-weapon; and that great shower of hailstones was shattered and dispersed on every side.
It does not describe Pralaya; it depicts localized cosmic-scale warfare imagery where Indra’s Vajra-astra neutralizes a destructive hail/stone downpour, showing divine control over violent natural forces.
By analogy, it models the ruler’s dharma of protection: just as Indra counters a calamity-like assault threatening all directions, a king is expected to deploy rightful force and strategy to remove widespread danger and restore order.
No direct Vastu or ritual procedure is stated; the key takeaway is the Purāṇic concept of astras as empowered ‘missiles’ whose correct deployment (like a consecrated act) can counter mass destruction—useful for interpreting later ritualized weapon-invocation motifs.