Developing Sustainable Schools in the Shadow of Active Stratovolcano: A Study at Disaster-Prone Areas of Merapi Volcano

Education is a right for people that must be given to children, even in an emergency of eruption disaster. To ensure the sustainable education during the crisis situations, ideas on how to develop a sustainable school system in the stratovolcano area which is prone to eruption disaster are needed. This research was conducted at schools located in the western side of Merapi Volcano, attempting to provide alternative information about the potential and role of schools in providing education during emergency situations of eruption disaster. Data in the study were collected through interviews, observations, remote sensing image interpretations, and documentations. Data were analysed by scoring and spatial analysis using geographic information systems. The results of the study are as follows. First, schools have the potential to provide education during the disaster emergency situations. School potential consists of physical infrastructure and human resource potential in the form of the role of the principal and teachers. Second, most of the level of school preparedness in facing disasters is still in the low category. This needs to be strengthened to ensure that the schools continue to function during the crisis period. Last, a division of roles in the sister school system is needed based on the location of the school toward the eruption centre. The schools in the safe zone act as a buffer for schools in vulnerable areas. Overall, schools have the potential to keep running the learning process during the crisis periods. This requires good management through the sister school system within the framework of sustainable school initiatives.

Magmatic clasts in the Saldanha ignimbrites, and Trekoskraal beach pebbles: missing pieces from the volcanic puzzle in the Cape Granite Suite

Previous studies have shown that the 542 Ma Saldanha eruption centre, situated on the west coast of South Africa, consists of the basal Saldanha Ignimbrite, which is partly intermingled with and partly overlain by the Jacobs Bay Ignimbrite, both having S-type characteristics. Together, the Saldanha eruption centre and the Postberg eruption centre (to the south, across Saldanha Bay) form part of the volcanic phase of the Cape Granite Suite. The lowermost parts of the Jacob’s Bay Ignimbrite contain magma clasts that are chemically dissimilar to their host ignimbrites. Some clasts are recrystallized ignimbrites that are chemically distinct from any unit that has outcrop expression, and are inferred to form part of a previously unrecognised volcanic event. Other clasts are non-fragmental, hypabyssal rocks that were evidently intruded prior to the explosive intracaldera eruptions that formed the Saldanha ignimbrites. Beach cobbles and pebbles, sampled from the Trekoskraal coastal area, include three texturally and chemically distinct groups – rhyolitic ignimbrites, rhyolitic hypabyssal rocks and dacitic hypabyssal rocks or lavas. Only a minority of these rocks (from the rhyolitic ignimbrite group) show some chemical affinities with the Saldanha Bay ignimbrites. The other pebble types show neither chemical nor textural similarities with the rocks of either the Saldanha or the Postberg eruption centres. The pebbles and cobbles also have no chemical affinities with any of the granitic intrusive rocks of the region. Their chemical and isotopic characteristics suggest that a variety of different magma batches were formed through partial melting of heterogeneous Malmesbury Group metamorphic rocks, at depth. LA-ICP-MS dating of igneous zircon crystals from two of the pebbles (a low-silica rhyolite ignimbrite and a dacite) yielded magmatic ages of 540 ± 4 Ma and 533 ± 4 Ma, respectively. Taking uncertainty brackets into account, these new dates suggest that there may have been a 3 Myr hiatus in eruptive activity, between the eruptions responsible for the exposed Saldanha ignimbrites and the eruptions that produced the volcanic units from which the pebbles were derived. This confirms the inference that there was a previously unidentified, later, volcanic event associated with the Cape Granite Suite in the Saldanha area.

Volcanic architecture, eruption mechanism and landform evolution of a Plio/Pleistocene intracontinental basaltic polycyclic monogenetic volcano from the Bakony-Balaton Highland Volcanic Field, Hungary

Bondoró Volcanic Complex (shortly Bondoró) is one of the most complex eruption centre of Bakony-Balaton Highland Volcanic Field, which made up from basaltic pyroclastics sequences, a capping confined lava field (~4 km2) and an additional scoria cone. Here we document and describe the main evolutional phases of the Bondoró on the basis of facies analysis, drill core descriptions and geomorphic studies and provide a general model for this complex monogenetic volcano. Based on the distinguished 13 individual volcanic facies, we infer that the eruption history of Bondoró contained several stages including initial phreatomagmatic eruptions, Strombolian-type scoria cones forming as well as effusive phases. The existing and newly obtained K-Ar radiometric data have confirmed that the entire formation of the Bondoró volcano finished at about 2.3 Ma ago, and the time of its onset cannot be older than 3.8 Ma. Still K-Ar ages on neighbouring formations (e.g. Kab-hegy, Agár-teto) do not exclude a long-lasting eruptive period with multiple eruptions and potential rejuvenation of volcanic activity in the same place indicating stable melt production beneath this location. The prolonged volcanic activity and the complex volcanic facies architecture of Bondoró suggest that this volcano is a polycyclic volcano, composed of at least two monogenetic volcanoes formed more or less in the same place, each erupted through distinct, but short lived eruption episodes. The total estimated eruption volume, the volcanic facies characteristics and geomorphology also suggests that Bondoró is rather a small-volume polycyclic basaltic volcano than a polygenetic one and can be interpreted as a nested monogenetic volcanic complex with multiple eruption episodes. It seems that Bondoró is rather a “rule” than an “exception” in regard of its polycyclic nature not only among the volcanoes of the Bakony-Balaton Highland Volcanic Field but also in the Neogene basaltic volcanoes of the Pannonian Basin.

Late Wenlock graptolite-bearing tuffaceous sandstone from Bomholm, Denmark

Late Wenlock (Silurian) graptoliferous dark grey mudstone and tuffaceous sandstone lithofacies occur, mainly as loose boulders, at the southeast coast of Bomholm. The mudstone may be estimated to repre­sent a 25 m thick sequence, and contains a graptolite fauna indicating the Cyrtograptus lundgreni Zone. The fauna is correlated with sequences of similar age from other areas, specially from Scania. Monograp-tus flemingi and Pristiograptus dubius pseudodubius are virtually the only species in the tuffaceous sandstone, some of which were deposited by turbidity currents. There is evidence from the taphonomy and diversity of the sandstone graptolites to suggest that the two species lived at a lower level in the water column than other, coexisting species. Size-frequency analyses are inconclusive as to whether or not the fauna in the tuffaceous sandstone represents a rapidly buried life-assemblage. The tuffaceous sandstone samples represent at least 3 airfall water deposited tuff beds and one bed deposited by turbidity current action. Mineral composition and grain-size of the tuffaceous sandstone indicate an origin from plinian eruptions at an estimated distance of about 300 km from Bomholm, and deposition at a depth of 1000 m ± 300 m, on the outer rim of the Fennoscandian platform. The volcanoes were probably situated on a continent south of Bomholm. The eruption centre later may either have disappeared within the Caledo­nian foldbelt or have been displaced by early Palaeozoic large-scale strike-slip faults towards the SE, along the SW border of the East-European craton.