A volcano is classed as active if it has erupted within the last 10 000 years, and active volcanoes can be erupting, dormant or in a phase of unrest. A volcano is erupting if it is producing tephra or lava, it is dormant if it is not erupting but has the potential to erupt in the future. Unrest is a transitional phase where a volcano shows increased signs of activity (seismic activity, releasing gas). When a volcano has been dormant for more than 10 000 years, it is considered extinct. Volcanoes can remain inactive, or dormant, for hundreds or thousands of years before erupting again. During this time, they can become covered by vegetation, making them difficult to identify. Compac stone isn’t only suited for standard uses & applications e.g. quartz worktops. There is an infinite range of decorative possibilities and solutions. Dining table tops, BBQ tops, paved shopping centre floors or cladded bar tops & walls. This company brings pigments, resins, ground stone + water-resistant agents, then combines them to create glistening marvels that also act as functional, practical tools facilitating everyday kitchen use. WOVO (2017) Word Organisation of Volcanic Observatories http://www.wovo.org/observatories/ [Date accessed 02/08/2017]

Unraveling the origin of volcanic lightninghas been difficult. In thunderstorms, the culprits are colliding ice crystals, which generate enough of an electric charge to trigger lightning. But ash clouds are less predictable and harder to study than supercells (thunderstorms), so scientists are still trying to figure out what sets off volcanic lightning. For instance, it seems absurd to blame ice for lightning in a volcanic inferno. Brantley SR, Geological survey (U.S.) (1990) The eruption of redoubt volcano, Alaska, December 14, 1989–August 31, 1990. U.S. Geological Survey circular, vol 1061. US Government Printing OfficeNowotny H (2005) The increase of complexity and its reduction: emergent interfaces between the natural sciences, humanities and social sciences. Theory, Culture Soc 22(5):15–31 +269 We are a family-run business, trading since 1983 (online since 2000), serving over half a million customers last year alone. As a five-time winner of the prestigious award “Best UK Online Retailer”, we are passionate about creating a shopping experience that is fun, easy and hassle-free.

The USGS established four key ‘standard’ requirements for VALS, which were to “(1) accommodate various sizes, styles, and duration of volcanic activity; (2) work equally well during escalating and de-escalating activity; (3) be equally useful to both those on the ground and those aviation; and (4) retain and improve effective existing alert notification protocol” (Gardner and Guffanti 2006, p. 1). Notably, three of these requirements are directly concerned not with scientific information as such but rather with function—the effectiveness and usability of the VALS as a communication tool. Ongoing standardisation processes were driven by a combination of factors: internationally by the adoption of the internationally used ICAO aviation colour code; nationally by the social context of the post-9/11 USA, which shaped the broader emergency management policy; at state level by the requirement to have consistent VALS and alert level terminology to prevent confusion; and internally within the USGS, to provide a more consistent and clear message. These standardisation processes are discussed in more depth in Fearnley et al. ( 2012).

The] complicated reduction of all of these factors (risk, hazard, activity) and boiling that down to a simple number [means] inevitably if you do that, something is going to be lost. You can’t just project a ten-dimensional problem down to one dimension and expect it to retain all its complexity (AVO scientist 4). USGS (2017) Volcano Notifications Deliver Situational Information. Retrieved from: https://volcanoes.usgs.gov/vhp/notifications.html. Accessed 4 Apr 2018 Finally, a study by Donovan et al. ( 2018) investigating risk perception at Popocatépetl volcano in Mexico (this volume) highlights important links between warnings and trust and the perceived motivation of particular groups, perceived trust and perceived knowledge. Following an online survey carried out from 2012 to 2014, their findings indicate that volcanic warnings and, more specifically, VALS are in fact effective, with greater level of risk perception in the public during raised alert levels as a result of higher activity, aiding to the communication and understandings of risk. Donovan et al. ( 2018) highlight the “importance of considering the social impact of warnings” (p?) whilst also emphasising that VALS act as a boundary object allowing “the translation of risk information into terms that people can understand” (p.?) between science and society, serving different functions on each side of that boundary. The key thing to note is that whilst the perceived knowledge of the volcano was the most important factor in explaining trust, VALS have considerable and complicated social impact. Studies such as these illustrate that there is still significant work to be done in exploring and evaluating VALS. Another key distinction that has developed as VALS have been designed and implemented around the world concerns two distinct institutional roles awarded to volcano observatories. In many countries, volcano observatories are classified as state or gederal services. This is the case for example in New Zealand and the USA, where such observatories are part of national research agencies required to provide a public interface (GNS and USGS respectively), in Japan and Iceland, where observatories are run from within National Meteorological Agencies, and in Mexico, where volcano observatories are run from within the Centro Nacional de Prevención de Desastres. These institutional arrangements and associated legal remits predispose the relevant observatories to interface with end users, since they are required to provide and prioritise public functions (typically of civil protection). However, in other countries, volcano observatories are situated within institutes with a predominantly scientific focus. In Ecuador, Italy and France, for example, the Instituto Geofisico, the INGV and Le Institut de Physique du Globe de Paris (IPGP) (respectively) are positioned in the science domain, which requires a primary focus on producing quality science. It is possible that institutional remits that require this more exclusive focus on scientific goals may result in VALS design and implementation less attuned to an interface function between scientific and end user communities. Papale’s ( 2017) defence of a clear division between scientific and operational functions, for example, could be interpreted in the light of this distinction, since he is based in an institute that focuses on producing scientific, rather than public service outcomes. We raise this point to note that this article draws from research conducted exclusively with USGS scientists and the associated range of USGS VALS end-users. Since the USGS is required to provide a public interface function, these research participants are likely to see the role of the volcano observatory framed in terms of direct utility serving society.