You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "what was the first sign that mt. pinatubo had awoken?" whose answer is March 15, 1991.
Each document should contain about 30 words, and these documents should contain useful information.

Query: first signs of mt. pinatubo activity
Useful Output:

Doc 1: International collaboration was notable at Mount Pinatubo--first  Early, perceptible signs from the volcano and prompt warning and mobilization
Doc 2:  volcano showed early signs of activity. "'Yung 1991, mabilis ang mga pangyayari. Nagkaroon ng phreatic eruption in April then June nag-erupt na.
Doc 3: Summit activity and seismicity, 1 July-15 October 1992. Pinatubo showed signs of renewed activity beginning in early July 1992, when low-frequency
Doc 4: Late June to early July 1991 – seismic activity reduced to 10 – 20 earthquakes per hour. Episodic bursts of seismic tremors with ash
Doc 5: Precursors at Mount Pinatubo included ash explosions at the summit, increases in the number of vents spewing hot gas, changes in the volcano's