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Volcano Tourism in the New Kanawinka Global Geopark of Victoria and SE South Australia 303

and at the eruption points perhaps large collapse often have other differences, which can be
calderas. characterized by the amounts and types of lava
Two classifications of types of eruptions and and ash produced, which are in turn related to
related landforms, based on several textbooks, are their chemical composition. The discussion which
given in Tables 20.1 and 20.2. follows deals with small volcanoes, which are
It can be argued that detailed classifications more directly relevant to geoparks.
such as these are not the best way to approach the
study and description of volcanic features, when Small (monogenetic) volcanoes
the audience may include mostly non-geologists. Numerous small scoria (cinder) cones, characterized
A simple geological and geomorphological by Strombolian/Hawaiian activity, broad but low
scheme of classification may be better, leaving elevation lava shields, explosive maar craters, and
more scope for discussions of non-geological associated and often long basaltic flows, 65km or
cultural heritage, including historic, artistic, longer, following pre-existing slopes and river
aesthetic and other values, which may be of equal valleys, are characteristic of monogenetic (single
or greater interest to many of the visitors to episode of activity) volcanoes. A single magma
volcanic areas. type, generally basalt, predominates in the activity,
The classification into eight types of eruptions which may continue over millions of years, with
(Table 20.1) can be simplified into just two main many short-lived individual volcanoes scattered
groupings of small and large volcanoes – that is, with a high density across a broad area; the
based on the size of the landform constructed at volcanism is often termed ‘areal’ or ‘polyorifice’ to
the eruption point. Small and large volcanoes describe the regional distribution.

Table 20.1 A classification of volcanic activity and landforms
Type Magma Flows and explosivity Landforms

Icelandic Basic, low viscosity Thick extensive flows from fissures, Lava shields and lava plains, with cones along fissures
weak explosivity
Hawaiian Basic, low viscosity Thin extensive flows from central Broad lava domes and shields, and long lava flows, fed
vents, weak explosivity, but by internal lava tubes, sometimes scattered scoria cones,
sometimes water-generated spatter cones, maar craters and tuff rings, built up by
phreatic explosions lava fountains, i.e. areal volcanic activity
Strombolian Moderate viscosity; Flows often absent, weak to Cinder (scoria) cones with shallow craters and short
mixed basic and acid violent explosivity flows; sometimes more extensive lava flows, scattered
scoria cones, spatter cones, maar craters and tuff rings,
built up by lava fountains, i.e. areal volcanic activity
Vulcanian Acid, viscous Flows often absent, moderate to Ash cones, explosion craters
violent explosivity
Vesuvian Acid, viscous Flows often absent, moderate to Large cones built up of alternating ash and lava, i.e.
violent explosivity stratovolcanoes, extensive ash fall, explosion craters and
large collapse calderas
Plinian Acid, viscous Flows may be absent, very violent Widespread pumice and ash deposits
explosivity

Pelean Acid, viscous Domes and/or short very thick Domes, spines, ash and pumice cones, ash flows forming
flows, nuées ardentes, moderate ignimbrite plains and plateaus
explosivity
Krakataun Acid, viscous No flows, cataclysmic explosivity Large explosion caldera
Source: Based on Ollier, 1969 and Gray, 2004; from Joyce, 2009

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