Nindiri pit crater

At the time of Oviedo's observations (1525), Nindiri crater was approximately 210 m deep, with a vent at the bottom hosting a lava lake. Nindiri is now filled by frozen lava lakes erupted between 1570 and 1670. A lava lake overflowed Nindiri to the north in 1670, forming a thick 3-km-long aa flow. The lava surface in the crater subsequently sagged downward on circular faults.

These faults, now cut by the San Pedro and Santiago crater walls, dip outward at approximately 807, and the lava flows are tilted inward. The faults extend down to the former crater floor of Nindiri, where they widen into broad fracture zones on the north side and join with a few main faults on the south side. A final lava lake was erupted onto the sagged crater floor. Spatter on the edge of San Pedro and within Nindiri indicates that this may be the lava flow described by Montesssus de Ballore. He reported that the flow was extruded in July 1852, a few years before the formation of Santiago and San Pedro pit craters in 1858-1859. (Excert from Rymer et al., 1998).