Determining whether a volcano is a cinder cone or a composite volcano
is important because its classification categorizes the magmatic syste
m and associated volcanic hazards, The criteria of age and size of the
volcano that are usually used for this assessment are inadequate for
active, young volcanoes, Other criteria on which that determination ca
n be based are magma production rates, cone morphology, and eruption s
tyle, Cerro Negro is an active, young, small basaltic volcano in north
western Nicaragua that is similar to both cinder cones and composite v
olcanoes in many ways. It has had at least 22 historically documented
eruptions since it first appeared in 1850; the most recent occurred in
late 1995. The magma production rate for Cerro Negro (similar to 1.6
km(3)/k.y.) is of the same magnitude as those of a variety of composit
e volcanoes and an order of magnitude higher than the production rate
for the Paricutin cinder cone region of the Trans-Mexican volcanic bel
t, Structurally, Cerro Negro's cone is a composite of scoria and lavas
cut by dikes around a dense volcanic core, Cerro Negro's shape has be
en more like a composite volcano than a cinder cone, except when infre
quent sub-Plinian eruptions have altered the cone to make it look like
a cinder cone, Comparisons of Cerro Negro to well-known, historically
active cinder cones and young composite volcanoes show that it is bes
t described as a young composite volcano, The future hazards posed by
Cerro Negro are, therefore, not those associated with cinder cone erup
tions, but the potentially more dangerous ones of composite volcanoes.