The first vibration of creation is called Shivatattva

निजेच्छया जगत्सृष्टमुद्युक्तस्य महेशितुः |
प्रथमो यः परिस्पन्दः शिवतत्त्वं तदुच्यते || 70 ||

While the great God was occupied with creating the universe of his own wish, the first vibration which (occurred) is called the Shiva element.