Recent (Quaternary) lava fields, such as those of
Citlaltépetl (Pico de Orizaba) volcano in Mexico, are
excellent places to obtain precise measurements of flow-field
dimensions that can be used to estimate volume, eruption duration and
effusion rates. The relationship between these parameters and the
influence of some other interrelated features such as lava
composition, superficial structures and lava type are important tools
that can help to infer conditions when the lavas were active and thus
improve understanding of how flow fields grow. The Holocene lavas of
Citlaltépetl volcano are homogeneous in composition (dacites)
and are generally blocky with well-developed levees. The eruption
duration obtained for the Citlaltépetl lavas by a method
proposed by C. Kilburn and R. Lopes presents a good correlation with
the different lava types morphologically classified here. Results
from that method compare favourably with the inferred effusion rates
estimated by an empirical cooling method (Graetz). The lavas show
different behaviour, mainly controlled by fluctuations in the
effusion rate that promote changes from single- to multiple-flow
style. The maximum distance achieved by a flow is directly
proportional to the effusion rate in Citlaltépetl lavas, but
it is always lower for multiple flows, independent of the volume of
erupted lava. Observations of Citlaltépetl lavas can be used
to understand how lava flow growth occurs on other
volcanoes.