Indonesia's volcanoes are places of recreation, aesthetic production, and scientific knowledge-gathering, as well as sites of pilgrimage, spirituality, and natural disasters for locals as well as international travellers. In this article, I focus on volcanoes as historic sites of labour to demonstrate the entanglement of colonial tourism and science with local forms of work and knowledge, and to reveal the origins of the porting and guiding work that takes place on Indonesia's volcanoes to this day. Using Tina Campt's method of “listening to images,” I show how colonial photographs, albeit partial sources, make modes of subaltern labour visible that written sources routinely minimised, restoring porters, guides, and what I call “camp domestics” to histories of service, science and geotourism in Indonesia. Recognising the homosocial setting of the colonial scientific expedition and the peculiar physical challenges of the volcano environment, I also examine the negotiation of Indonesian and European masculinities and their intersection with class and racial hierarchies on the volcano. The article thus reflects on how Javanese workers’ spatial and social mobility entailed the negotiation of opportunity as well as exploitation on tour.

In volcano-tectonic regions, dyke propagation from shallow magmatic chambers is often controlled by the interaction of the local and regional stress fields. The variations of the stress fields result from a combination of factors including the regional tectonic stress, the geometry of pressurized magma chambers, the layering and the pre-existing discontinuities (e.g. fractures). In this contribution, we describe and apply a new multiparametric inversion technique based on geomechanics that can invert for both the far field stress attributes and the internal pressure of magma chambers or stocks, constrained by observed dyke or eruptive fissure orientations. This technique is based on the superposition principle and uses linear elastic models that can be solved using many types of numerical methods. For practical reasons, we chose a 3D boundary element method (BEM) for a heterogeneous elastic half-space, where magma chambers are modelled as pressurized cavities. To verify this approach, the BEM solution has been validated against the known 3D analytical solution of a pressurized cylindrical cavity. Then the effectiveness of this technique and its practical use is demonstrated through application to natural examples of dyke network development around two different volcanic systems, the Spanish Peaks (USA) and the Galapagos Islands (Ecuador). Results demonstrate that regional stress characteristics as well as the internal pressure of magma chambers can be estimated from observed radial and circumferential dyke patterns and some knowledge of magma chamber geometry.

During the eighteenth century, chemists in the Kingdom of Naples (the South of Italy) were very busy analyzing the chemical composition of ash from Mount Vesuvius. Undoubtedly, after a huge eruption this dusty phenomenon was the most important scientific object of debate. In fact, it was crucial to determine if there were dangerous elements in the ash so that the population could be warned about the potential hazards, such as polluted drinking water. This was not at all a simple issue, as on the other hand there were scholars who realized that ash could be beneficial as a fertilizer, even as clouds of ash had obscured the sun. As chemical inquiries became more precise and the toxic concentration of many elements became known, this double life of Vesuvian ash as a scientific object gradually died.

Major and trace element and Sr, Nd and O isotopic data are presented for ferrobasalts, icelandites, rhyolites, mixed pumices and silicic xenoliths of the 1875 eruption of Askja. Trace element modelling and Sr and Nd data largely confirm previous major element calculations that fractional crystallization was dominant in the generation of the basalt-ferrobasalt-icelandite-rhyolite suite. Relative enrichment in Rb (and Th and U?), depletion in Cs, and low values of δ18O/16O, in the rhyolites are not explained by this mechanism alone. The silicic magmas were selectively contaminated by diffusion from partially molten granitic wall rocks, now found as xenoliths in the eruptive products, the process being particularly marked by lower δ18O and Cs/Rb ratios in the rhyolites than in the associated basalts. This is the first record of a combined fractional crystallization-selective contamination process in an Icelandic silicic complex.

Lake sediment cores from Midge Lake, Livingston Island, South Shetland Islands and Sombre Lake, Signy Island, South Orkney Islands were analysed for volcanic tephra using light microscopy and magnetic susceptibility. Cores were dated using published 14C and 210Pb chronologies. Electron probe microanalyses of discrete tephra glass shards were undertaken to characterise the tephra geochemically in order to identify possible source volcanoes and refine tephrochronological data for the region. Results identified five tephra horizons in a core from Midge Lake. Four of these tephra at 3–4 cm, 8–9 cm (c. 450 yr BP), 15–16 cm (c. 755 ± 105 yr BP) and 21–22 cm (c. 1340 ± 100 yr BP) consisted of sodic basaltic to basalticandesitic glasses, containing abundant labradoritic feldspar inclusions, and a single ‘acidic’ tephra was found at 2–3 cm. Seven tephra horizons were identified in the Sombre Lake core including three basaltic tephra at 3–9 cm (30 ± 4 yr BP to 125 ± 25 yr BP), 31–32 cm and 44–46 cm (1325 ± 50 14C yr BP) and four acidic tephra at 21–22 cm and 24–25 cm, 33–36 cm (c. 1021 14C yr BP) and 54–56 cm (c. 1450 14C yr BP). These are the first tephra to be identified from the South Orkney Islands. Geochemical and grain size analysis indicated that the analysed Midge Lake tephra were derived from the Quaternary Deception Island volcano. Smaller grain sizes, congruent geochemical data and prevailing wind directions also indicate this volcano as the likely source of Sombre Lake tephra. Results highlight the importance of establishing geochemical consistency between tephra deposited across wide geographical areas, during apparently synchronous time periods, if they are to be used in a regional tephrochronology.