2.2. Volcano Monitoring
A volcano monitoring system aims to gather the maximum
relevant information about the volcanic activity in order to
detect precursory signals of an impending hazardous event.
For that purpose, it is important that the monitoring system
is in place well in advance of the eruptive crisis in order to
establish a baseline of activity against which anomalies can
be compared. These systems consist of the instrumentation
of the volcano with specialized measuring equipment
adequate for timely detection of any geophysical or
geochemical changes of the volcano for correct decision-
making and management of a possible emergency.
Here we define “minimum monitoring” as basic instru-
mentation that should allow the detection of the first
symptoms of reactivation. This is subjective and will depend
on the activity of the volcano. In some countries, an over-
view of different levels of monitoring for different levels of
volcanic risk has been undertaken to guide how to best focus
resources. Monitoring technology is developing rapidly, and
the ability to install basic, cheap, and robust monitoring
instrumentation is improving. In addition, remote moni-
toring through satellite observations can be a cost-effective
way of observing changes at multiple volcanoes if there
are insufficient resources to implement ground-based
monitoring.
Once eruption precursors increase, the monitoring sys-
tem should be augmented. More complete monitoring will
encompass a wider set of geophysical or geochemical
parameters, with data analyzed in real time (s) or near real
time (min). Campaign monitoring can be added where staff
and expertise is available. Ideally, a monitoring system
should be designed with the ability to add more instru-
mentation quickly and easily during a crisis response.
All high-risk volcanoes should have a comprehensive
and long-term monitoring system, especially those vol-
canoes that are frequently active; however, resource limi-
tations might mean that a country will need to rely on an
approach of minimum monitoring in the long term, with the
ability to augment the networks during a crisis response.