Aerial view WSW of Pu'u O'o and the paths of lava flows that spilled over its east crater rim (light gray areas in photo center) on July 19 and 29 and August 6 (lava also spilled over the east rim on September 28). The level of the lava pond inside Pu'u O'o between June and late September varied from as deep as about 45 m below the east crater rim when lava drained freely back into the ground to overflowing when the subsurface drainage cracks and fractures became blocked temporarily. Lava overflowed the east rim, west rim, or both, depending on the rate of filling and which way lava flowed from the inner crater cone.