The Cerro Quemado dome complex, buttressed to the north by La Pedrera, postdates the La Pedrera flows. Lava flow morphologies and radiocarbon ages indicate that dome growth is limited to late Holocene time. Based on cross-cutting relationships, 4 volcanic units are identified at Cerro Quemado.
Stratigraphic summary of principal units at Cerro Quemado Volcano.

During stages I and II, voluminous flows and domes in the central and southern sectors of the complex were erupted from a circular arrangement of at least 8 vents. A typical eruption produced a viscous blocky lava flow, and subsequent plug dome at the vent. The Paxmux flow extends 2.5 km from its vent 0.5 km east of the dome and temporarily dammed the Río Samalá. The Paxmux flow does not overlap other units of the complex but is considered part of Cerro Quemado because of its compositional and morphological similarity.

In contrast to earlier activity, stage III volcanism was in part explosive. Events of this period included: dome growthy, catastrophic edifice collapse and debris avalanche; a laterally directed blast and associated pyroclastic flows; and emplacement of small debris flows. The presence of non-vesiculated, prismatic, juvenile dome rock in late stage III volcaniclastic deposits suggests that this stage began with dome growth along the western flank of Cerro Quemado. An edifice-collapse event and debris avalanche either immediately following or concomitant with dome growth, however, destroyed the early stage III dome. Edifice collapse at Cerro Quemado was followed by a laterally directed blast and an associated pyroclastic flow that covered the LLano del Pinal valley and overwhelmed the east flank of Siete Orejas. Stage III ended with reneewed dome growth and emplacement of a small Peleéan dome in the upper-central part of the scarp.

The timing of edifice collapse is constrained by radiocarbon ages from charcoal admixed with associated lateral blast and pyroclastic flow deposits. Calibrated ages for five charcoal samples give a range of 797 to 1409 years B.P. Sample #2 consists of carbonized twigs and stems, presumably from a juvenile plant, and has a calibrated age of approximately 1150 yr B.P. This age is similar to that of sample #3 and is intermiediate to those of samples # 1, 4, and 5. A weighted average of all five samples yields a calibrated age of about 1150 years B.P. Apparently, both edifice collapse and subsequent pyroclastic activity occurred at about this time.

Radiocarbon ages from the stage III pyroclastic deposits at Llano del Pinal. Photo by Conway et al., 1993.

In January 1818, following nearly 700 years of repose, a blocky lava flow erupted from the east-central flank of Cerro Quemado. Minor pyroclastic eruptions accompanied extrusion and covered nearby hills with up to 1 m of tephra. Residents reported that earthquakes preceded and occurred throughout the eruption.

(Conway et al., 1992)