How deep is Mount Pinatubo crater lake?

Various websites give contradictory and confusing information about Pinatubo crater lake depth. Phivolcs (the Philippine Institute of Volcanology and Seismology) states a depth of 600 to 800 meters(1), an article of the Journal of the Japan Society of Engineering Geology mentions 600 meters(2), an article in one of the main country's newspaper says 87 meters(3).

Let's now check several facts:
- Mt. Pinatubo summit had an elevation of 1745 meters before the 1991 eruption
- since the 1991 eruption its highest point is 1485 meters(4)
- just after the eruption the elevation of the caldera floor was established at around 800 meters above see level(5).
- elevation at the surface of the crater lake is around 900 meters above see level(6).

Which gives us an average depth of 100 meters.
This is confirmed by the study below(a). Coupled sonar and GPS mapping were used to give the following results:
- the deepest point of the lake floor is at 780 meters asl
- the lake shore is at 890 meters asl

(a)Geology and hazard implications of the Maraunot notchin the Pinatubo Caldera, PhilippinesA. M. F. Lagmay, , K. S. Rodolfo, F. P. Siringan, H. Uy, C. Remotigue, P. Zamora, M. Lapus, R. Rodolfo, J. Ong

(5)Volcanoes of the World - By Lee Siebert, Tom Simkin, Paul Kimberly
(6)Verified during TRIPinas treks with our GPS.