ABSTRACT
This chapter provides an overview of seismic monitoring, and focuses on current trends in both hardware development and network design and operation. Monitoring tremor at one station only, as is often the case at active volcanoes, will not allow for separating the source from the host-medium effects, whenever the tremor source is constant in space and time. Automated detection and processing of seismic events is probably the most significant recent innovation in volcano surveillance-oriented seismology, and it is easy to envisage this procedure playing an increasingly important role in computer-assisted civil protection decisions related to eruptive activity. As well as accurately constraining the locations of hypocentres, it is also important to have the capability of monitoring the migration of the seismic sources with time, as this may provide a guide as to what the volcano might do next.
