Lava

The felsic lavas of the Bamenda Mountains, in the main part of the Cameroon Volcanic Line, are mainly represented by trachytes, with subordinated benmoreites and alkaline to peralkaline rhyolites. New K–Ar geochronological data define two main volcanic episodes, the first one between 18 and 22Ma, and the second one from 12.5 to 13.5Ma. Geochemical data indicate that these felsic rocks

Although the potential hazards associated with an eruption of Nevado del Ruiz volcano were known to civil authorities before the catastrophic eruption there in November 1985, their low perception of risk and the long quiescent period since the last eruption (140 years), caused them to wait for stronger activity before developing an eruption alert system. Unfortunately, the eruption occurred suddenly after a period of relative quiet, and as a result more than 25,000 people were killed. Although it was accurate and reasonably comprehensive, the hazard map that existed before the eruption was poorly understood by the authorities and even less so by the general population, because the scientific terminology and probabilistic approach to natural hazards were unfamiliar to many of them. This confusion was shared by the communication media, which at critical times placed undue emphasis on the possibility of lava flows rather than on the more imminent threat from mudflows, in keeping with the popular but often inaccurate perception of volcanic eruptions. This work presents an updated hazard map of Nevado del Ruiz that combines information on various hazardous phenomena with their relative probability of occurrence in order to depict numerical "hazard levels" that are easily comprehensible to nonspecialists and therefore less susceptible to misinterpretation. The scale of relative risk is arbitrary, ranging from five to one, and is intended to provide an intuitive indication of danger to people, property and crops. The map is meant to facilitate emergency preparedness and management by political and civil authorities, to educate the public concerning volcanic hazards and to assist in land-use planning decisions.

A wide variety of environmental records is necessary for analysing and understanding the complex Late Quaternary dynamics of permafrost-dominated Arctic landscapes. A NE Siberian periglacial key region was studied in detail using sediment records, remote sensing data, and terrain modelling, all incorporated in a geographical information system (GIS). The study area consists of the Bykovsky Peninsula and the adjacent Khorogor Valley in the Kharaulakh Ridge situated a few kilometres southeast of the Lena Delta. In this study a comprehensive cryolithological database containing information from 176 sites was compiled. The information from these sites is based on the review of previously published borehole data, outcrop profiles, surface samples, and our own field data. These archives cover depositional records of three periods: from Pliocene to Early Pleistocene, the Late Pleistocene and the Holocene. The main sediment sequences on the Bykovsky Peninsula consist of up to 50 m thick ice-rich permafrost deposits (Ice Complex) that were accumulated during the Late Pleistocene. They were formed as a result of nival processes around extensive snowfields in the Kharaulakh Ridge, slope processes in these mountains (such as in the Khorogor Valley), and alluvial/proluvial sedimentation in a flat accumulation plain dominated by polygonal tundra in the mountain foreland (Bykovsky Peninsula). During the early to middle Holocene warming, a general landscape transformation occurred from an extensive Late Pleistocene accumulation plain to a strongly thermokarst-dominated relief dissected by numerous depressions. Thermokarst subsidence had an enormous influence on the periglacial hydrological patterns, the sediment deposition, and on the composition and distribution of habitats. Climate deterioration, lake drainage, and talik refreezing occurred during the middle to late Holocene. The investigated region was reached by the post-glacial sea level rise during the middle Holocene, triggering thermo-abrasion of ice-rich coasts and the marine inundation of thermokarst depressions.

Resumen: A finales del año 2017, se empezó el desarrollo de un prototipo de caja de arena denominado “GS-Sandbox”, iniciativa motivada por revisar técnicas elaboradas en museos interactivos como en Japón, sitios donde se han implementado las técnicas de Realidad Aumentada para concientizar a los ciudadanos japoneses acerca de los fenómenos naturales que se registran año tras año. El objetivo de este estudio es replicar un dispositivo de modelamiento topográfico de realidad aumentada (AR) sobre una caja de arena. Esta será una herramienta interactiva para concientizar a estudiantes de escuelas, colegios, comunidad y entidades gubernamentales acerca de los peligros de los fenómenos naturales, principalmente los que están relacionados con las erupciones volcánicas en el Ecuador. La realidad aumentada se produce al superponer elementos virtuales sobre elementos reales y al utilizar la tecnología informática puede ser visualizado en una pantalla o proyectado al mundo real.

Conventional building methods are continuing to stress the supply of available resources, including water, energy and materials, causing harm to the environment. In order to tackle these problems the building industry needs to embrace sustainable development methods and policies. One of the main approaches used to define and give solutions to these problems is adopting the relatively newly founded buildings and communities certification systems. As these certification systems are tremendously growing, it is important to continually examine their effectiveness, development path and results.
The objective of the proposition is to better understand the impacts, opportunities and challenges of the use of any certification system, by showcasing “Estidama”, Abu Dhabi’s certification system, addressing the local environment, social, economic and culture aspects. This is assisted by a local case study “Masdar City”, presenting two levels of study, the building and community scales. The research methods include examining available literature, as well as on site Interviews with clients, designers, engineering consultants, environmental consultants, project managers, contractors, facility managers, building information modeling experts, municipal officials, credits assessors, policy writers and government representatives, in an attempt to represent the collaborative effort from all parties involved in any project.
The interview results, as well as specific credits analyzed helped accomplishing the aim of sensitizing stakeholders and regulatory bodies about the benefits and deficiencies of rating systems. Furthermore a development of recommendations formulated in form of strategies and an action plan are presented, to aid enhancing new and existing certification procedures.

Keywords:
Architecture Sustainable Transportation Sustainable Development Environmental Planning and Design Urban Planning Sustainable Building Design Sustainable Urban Environments Sustainable Water Resources Management Sustainable Energy Green architecture Environmental Sustainability Sustainable Architecture Sustainable Design Green Building LEED Certification Thesis Master's Thesis Abu Dhabi Resource efficiency Building Energy Certificates BREEAM Zero-energy buildings Masdar City Green Building Certification Estidama Abu Dhabi Education Council Abu Dhabi Urban Planning Council Urban Planning Council

All versions of the Ramayana are unanimous in reiterating Sita Ji's fidelity and devotion towards Rama even in times of extreme adversity. For example, when Shri Rama is preparing to go to exile in the forest all alone, she addresses him thus: "O son of an illustrious monarch, a father, a mother, a brother, a son or a daughter-in-law, all enjoy the fruit of their karma individually and receive what is their due. It is only the wife who actually shares the fortunes of her husband. When you depart this day for the dense forests which are difficult to penetrate, I shall walk ahead of you crushing under my feet, all the thorns that lie on your way."

A new category of large-scale volcanism, here termed Snake River (SR)-type volcanism, is defined with reference to a distinctive volcanic facies association displayed by Miocene rocks in the central Snake River Plain area of southern Idaho and northern Nevada, USA. The facies association contrasts with those typical of silicic volcanism elsewhere and records unusual, voluminous and particularly environmentally devastating styles of eruption that remain poorly understood. It includes: (1) large-volume, lithic-poor rhyolitic ignimbrites with scarce pumice lapilli; (2) extensive, parallel-laminated, medium to coarse-grained ashfall deposits with large cuspate shards, crystals and a paucity of pumice lapilli; many are fused to black vitrophyre; (3) unusually extensive, large-volume rhyolite lavas; (4) unusually intense welding, rheomorphism, and widespread development of lava-like facies in the ignimbrites; (5) extensive, fines-rich ash deposits with abundant ash aggregates (pellets and accretionary lapilli); (6) the ashfall layers and ignimbrites contain abundant clasts of dense obsidian and vitrophyre; (7) a bimodal association between the rhyolitic rocks and numerous, coalescing low-profile basalt lava shields; and (8) widespread evidence of emplacement in lacustrine-alluvial environments, as revealed by intercalated lake sediments, ignimbrite peperites, rhyolitic and basaltic hyaloclastites, basalt pillow-lava deltas, rhyolitic and basaltic phreatomagmatic tuffs, alluvial sands and palaeosols. Many rhyolitic eruptions were high mass-flux, large volume and explosive (VEI 6–8), and involved H2O-poor, low-δ18O, metaluminous rhyolite magmas with unusually low viscosities, partly due to high magmatic temperatures (900–1,050°C). SR-type volcanism contrasts with silicic volcanism at many other volcanic fields, where the fall deposits are typically Plinian with pumice lapilli, the ignimbrites are low to medium grade (non-welded to eutaxitic) with abundant pumice lapilli or fiamme, and the rhyolite extrusions are small volume silicic domes and coulées. SR-type volcanism seems to have occurred at numerous times in Earth history, because elements of the facies association occur within some other volcanic fields, including Trans-Pecos Texas, Etendeka-Paraná, Lebombo, the English Lake District, the Proterozoic Keewanawan volcanics of Minnesota and the Yardea Dacite of Australia.

The Sterkspruit Complex, exposed at the base of the Karoo flood basalts in South Africa, is a complex of mostly massive volcaniclastic rocks, dikes and lava that fills a crater N 45 km 2 cut into country rock and is surrounded by a blanket of more-distal bedded volcaniclastic rocks. The moderately to steeply inward-dipping margins of the crater are delineated by country-rock breccia that grades into rocks within the complex. Intracomplex rocks are dominated by massive, polymict lapilli tuff and tuff breccia N150 m thick, with intercalated lavas, and minor bedded volcaniclastic rocks. Pillow lava N 50 m thick and thinly bedded, inferred lacustrine deposits cap the complex succession and are in turn covered by subaerial Karoo flood basalts. Beyond the crater a succession of bedded, finer-grained volcaniclastic rocks (100-60 m thick) rests on country rock and thins distally over at least 5 km.

Electrical borehole wall images represent micro-resistivity measurements at the borehole wall. The lithology reconstruction is often based on visual interpretation done by geologists. This analysis is very time-consuming and subjective. Different geologists may interpret the data differently. In this work, linear discriminant analysis (LDA) in combination with texture features is used for an automated lithology reconstruction of ODP (Ocean Drilling Program) borehole 1203A drilled during Leg 197. Six rock groups are identified by their textural properties in resistivity data obtained by a Formation MircoScanner (FMS). Although discriminant analysis can be used for multi-class classification, non-optimal decision criteria for certain groups could emerge. For this reason, we use a combination of 2-class (binary) classifiers to increase the overall classification accuracy. The generalization ability of the combined classifiers is evaluated and optimized on a testing dataset where a classification rate of more than 80% for each of the six rock groups is achieved. The combined, trained classifiers are then applied on the whole dataset obtaining a statistical reconstruction of the logged formation. Compared to a single multi-class classifier the combined binary classifiers show better classification results for certain rock groups and more stable results in larger intervals of equal rock type.

Volcán Tancítaro is a 97 ± 3 km 3 stratovolcano located in the Michoacán Guanajuato volcanic field (MGVF), part of the Trans Mexican Volcanic Belt. Prior to this study, there was only one K-Ar date (530 ± 60 ka; . K-Ar ages of lavas from shield volcanoes in the Michoacán-Guanajuato volcanic field, Mexico. Geofisica Internacional 31 (4), 467-473.] and one sector-collapse event reported for this volcano in the literature [Garduño-Monroy V.H., Corona-Chavéz, P., Israde-Alcantara, I., Mennella, L., Arreygue, E., Bigioggero, B., Chiesa, S., 1999. Carta Geológica de Michoacán, scale 1:250,000. Universidad Michoacana de San Nicolás de Hidalgo.; Capra, L., Macías, J.L., Scott, K.M., Abrams, M., Garduño-Monroy, V.H., 2002. Debris avalanches and debris flows transformed from collapses in the Trans-Mexican Volcanic Belt, Mexico -Behavior, and implications for hazard assessment. Journal of Volcanology and Geothermal Research 113, 81-110.]. Twenty-six new 40 Ar/ 39

The North Atlantic Igneous Province (NAIP) is a large igneous province (LIP) that includes a series of lava suites erupted from the earliest manifestations of the (proto)-Icelandic plume, through continental rifting and ultimate ocean opening. The lavas of one of these sub-provinces, the British Palaeogene Igneous Province (BPIP), were some of the first lavas to be erupted in the NAIP and overlie a thick crustal basement and sedimentary succession with abundant S-rich mudrocks. We present the first platinum-group element (PGE) and Au analyses of BPIP flood basalts from the main lava fields of the Isle of Mull and Morvern and the Isle of Skye, in addition to a suite of shallow crustal dolerite volcanic plugs on Mull, and other minor lavas suites. BPIP lavas display both S-saturated and S-undersaturated trends which, coupled with elevated PGE abundances (N MORB), suggest that the BPIP is one of the most prospective areas of the NAIP to host Ni–Cu–PGE–(Au) mineralisation in conduit systems. Platinum-group element, Au and chalcophile element abundances in lavas from West and East Greenland, and Iceland, are directly comparable to BPIP lavas, but the relative abundances of Pt and Pd vary systematically between lavas suites of different ages. The oldest lavas (BPIP and West Greenland) have a broadly chondritic Pt/Pd ratio (~ 1.9). Lavas from East Greenland have a lower Pt/Pd ratio (~ 0.8) and the youngest lavas from Iceland have the lowest Pt/Pd ratio of the NAIP (~0.4). Hence, Pt/Pd ratio of otherwise equivalent flood basalt lavas varies temporally across the NAIP and appears to be coincident with the changing geodynamic environment of the (proto)-Icelandic plume through time. We assess the possible causes for such systematic Pt/Pd variation in light of mantle plume and lithospheric controls, and suggest that this reflects a change in the availability of lithospheric mantle Pt-rich sulphides for entrainment in ascending plume magmas. Hence the precious metal systematics and potential prospectivity of a LIP may be affected by contamination of plume-derived magmas by subcontinental lithospheric mantle at the margins of cratons that have been enriched by Palaeoproterozoic orogenesis.

A NNW-trending belt of alkaline mafic volcanic fields parallels the Gulf of Mexico from the U.S. border southward to Veracruz state, in eastern Mexico. Previous studies grouped this volcanism into the so-called bEastern Alkaline ProvinceQ (EAP) and suggested that it resulted from Gulf-parallel extensional faulting migrating from north to south from Oligocene to Present. On the basis of new geologic studies, forty-nine unspiked K-Ar and two 40 Ar-39 Ar ages, we propose a new geodynamic model for the volcanism along the southwestern Gulf of Mexico.

Deposits of the 15.8 Ma Nuraxi explosive eruption crop out in the Sulcis volcanic district, southwestern Sardinia. They consist of a decimeter-thick pumice fallout layer overlain, with no apparent temporal break, by several tens of meters thick, high-grade ignimbrite. The eruption was from a vent probably located~20-30 km north of S. Pietro island, and it tapped a compositionally uniform, rhyolite magma reservoir (SiO 2 70-72 wt.%) bearing about 20 vol.% crystals. The ignimbrite consists of: (a) a Lower Ignimbrite (LI), b2-m-thick, fine-grained and glassy grading upward into a partly devitrified lapilli-tuff, and (b) an Upper Ignimbrite (UI) that is an intensely welded to lava-like lapilli-tuff. The deposit has an inferred maximum runout of about 80 km and overall dispersal/thickness characteristic of a low aspect-ratio ignimbrite.

Recovering physical properties such as attenuation and velocity of the Earth's heterogeneities is as important as recovering the shape and the surface reflectivity of the heterogeneities themselves. A reliable estimate of attenuation in the Earth is necessary to improve our knowledge of subsurface physical properties like the degree of fluid saturation. Moreover the attenuation may also be relevant to 'bright spot' studies in reservoir characterization. Within this context, this paper presents applications of asymptotic viscoacoustic waveform inversion to synthetic and ultrasonic laboratory data recorded to characterize the velocity and attenuation of a lava sample collected on the Vesuvius volcano.

Mt. Merapi, Indonesia, is one of the most active and dangerous volcanoes in the Torrid Zone. This volcano has erupted frequently and has produced pyroclastic flows following the collapse of the summit lava dome. We used Synthetic Aperture Radar (SAR) data acquired by JERS-1 and RADARSAT-1 satellites from April 1996 to July 2006 to clarify the distribution patterns of the pyroclastic flow deposits. The extent of the deposits, termed P-zones, was accurately extracted by ratio operation and low-level feature extraction from SAR intensity images. These images highlighted temporal changes of the distribution area, perimeter, flow distance, included angle, and collapse direction. To validate the image-processing results, reflectance spectra of the rock samples collected after the eruption in June 2006 were measured in a laboratory. The reflectance spectra of all samples showed similar characteristics to the reference spectra, which were derived from atmospheric correction of Hyperion sensor image data covering the lava dome at the summit. Therefore, P-zones were confirmed to be the pyroclastic flow deposits originating from destruction of the lava dome at the summit. The image-processing results clarified that the extent of the distribution areas, perimeter, flow distances, and included angle of the P-zones were variable among the eruptions, while the collapse direction had a constant pattern. The collapse pattern followed a clockwise change from the south toward the west. By comparing the ratio maps of Bouguer gravity anomaly data in two periods, the change was interpreted to originate from the inclination of the conduit and the formation of shallow and deep magma reservoirs.

The 1960 rhyodacitic fissure eruption in the Cordo´n Caulle Volcanic Complex (CCVC), located in Southern Andes (40.58S) was a unique volcanic episode. The remarkable eruption was triggered by the greatest recorded subduction-zone earthquake, starting 38 h after the main shock, 240 km inland. The structural behaviour, two compound fissures opening along a margin- oblique (NW) structure related to the

1] A commonly used method to convert lava flow area to volume flux using low spatial resolution satellite data rests on two primary assumptions, that: (1) volume flux is related to flow area, and (2) lava surfaces cool exponentially with time and distance from the source. Field data show that both assumptions are valid. The ensuing relationship is an empirical one in which flow area is proportional to timeaveraged discharge rate under given compositional, insulation, rheological and ambient conditions. Thus, the proportionality has to be determined depending on flow conditions, and the conversion set and applied on a case-bycase basis. Citation: Harris, A. J. L., and S. M. Baloga Lava discharge rates from satellite-measured heat flux, Geophys.

Multiphase (MP) and low frequency (LF) earthquakes with spectral peak amplitudes at 3-4 and 1 Hz, respectively, are two common types of shallow volcanic earthquakes previously recognized at Merapi Volcano. Their mechanisms are poorly understood but MPs have been temporally associated with lava dome growth. We conducted a seismic experiment in January-February 1998, using four broadband seismographs to investigate the nature of seismic activity associated with dome growth. During our experiment, Merapi experienced mild dome growth with low-level seismic activity. We compare our data to that recorded on a local short-period (SP) network, with the following preliminary results.

This paper demonstrates that four large sector collapses have affected the NW flank of the Stromboli volcano in the past 13 ka, alternating with growth phases. In order to contribute to the evaluation of the critical conditions which trigger lateral collapses, a reconstruction of the geometry of each collapse of the volcano edifice in the four stages that preceded the relative collapse events is also presented, and a computation of the landslide volume. This reconstruction is based on new field data plotted in three dimensions. Prior to the initial 13-ka collapse, the volcano was 1125±100 m high above sea level. The collapse had a volume of 2.23±0.87 km 3 , whereas the pre-collapse volcano volume was 218.8± 7.7 km 3 . The next edifice that failed was 900±70 m high a.s.l. The collapse volume was 1±0.54 km 3 , with a precollapse volcano volume of 201.4±5.4 km 3 . The edifice then grew to 1000±60 m a.s.l. The third collapse had a volume of 1.08±0.39 km 3 and occurred within a volcano with a volume of 209.1±4.6 km 3 . This was followed by a new growth phase followed by the last collapse with a volume of 0.73±0.22 km 3 . The volcano volume was about the same as the present one. The present active crater zone is at 780 m a.s.l. In the first three collapses, sliding surfaces cut the main magma conduit. In the last collapse, the upper scarp coincided with the conduit location. Dyking along a main NE-trending weakness zone across the volcano summit exerted a lateral force for collapse inception. The decrease of the landslide volumes with the age, and the concentric scarps of the four collapses, suggest that the younger sliding planes tended to become more superficial and to decrease the areal extent. This is interpreted as due to: (a) successively weaker eruptive products from dominantly lavas to dominantly pyroclastics; and (b) the feedback effects between collapses and dykes that injected along the lateral segments of the first collapse slide plane.

Iceland mid-ocean ridge magma chambers crustal interaction MORB igneous petrology Volcanic eruptions in Iceland occur either from fissures or central vents (lava shields). Within the post-glacial Western Volcanic Zone, the Thjófahraun fissure-fed lava field and Lambahraun lava shield were both erupted 4000 yrs B.P. with eruptive centers separated by only~25 km. Thjófahraun erupted~1 km 3 of pāhoehoe and 'a'ā lava from a 9-km long fissure, whereas the Lambahraun lava shield erupted N 7 km 3 of low effusion-rate pāhoehoe. Thjófahraun lavas contain higher K, Rb, Y and Zr, and lower CaO than Lambahraun lavas at the same MgO, with variations broadly consistent with evolution by low-pressure crystal fractionation. Lambahraun spans a larger range of MgO, which generally decreases over time during the eruption. Lambahraun samples with high Al 2 O 3 and low TiO 2 and FeO likely reflect up to 15% plagioclase accumulation. In addition, all samples from Lambahraun exhibit increasing CaO and Nb/Zr with decreasing MgO and overall incompatible-element enrichments greater than predicted by crystal fractionation alone. Although the increase in Nb/Zr and other incompatible elements could be explained by gradually more incompatible-element enriched parental magma being supplied to the magmatic system during the course of the Lambahraun eruption, this process requires very small-scale trace element heterogeneities in the mantle that are apparently decoupled from isotopic variations and a systematic relationship between parental magma composition and extent of differentiation. Alternatively, correlations among incompatible element concentration, increasing differentiation and time during the eruption can be related by concurrent wallrock assimilation and crystallization during melt migration through the crust. Geochemical modeling of assimilation of wallrock clinopyroxene concurrent with crystallization of olivine (± plagioclase) effectively reproduces the observed chemical variations of Lambahraun samples. Similar chemical characteristics exist in several other Western Volcanic Zone lava shields but not in fissure eruptions. Magmas that fed fissure eruptions may also have been modified by interaction with the crust prior to aggregation in crustal magma chambers, but the geochemical signature of this process is obscured by magma mixing. In contrast, Icelandic lava shields that preserve deeper level processes may not have developed shallow magma chambers; rather they probably represent slow effusion from magma systems that are continually being recharged and reacting with the crust during the course of their eruptions.

Kulshan caldera (4.5×8 km), at the northeast foot of Mount Baker, is filled with rhyodacite ignimbrite (1.15 Ma) and postcaldera lavas and is only the third Quaternary caldera identified in the Cascade arc. A gravity traverse across the caldera yields a steep-sided, symmetrical, complete Bouguer anomaly of −16 mGal centered over the caldera. Density considerations suggest that the caldera fill,

1] The NZAPLUME III expedition of September-October 2004 to the northern Kermadec-southern Tofua (NKST) arc, between 28°52 0 S and 25°07 0 S, resulted in the discovery of at least seven new submarine volcanic centers and a substantial caldera complex adjacent to the previously known Monowai Seamount. The volcanic centers form a sublinear chain that coincides with the Kermadec Ridge crest in the south (Hinetapeka) and diverges $45 km westward of the ridge crest in the north (''V'') just to the south of where the Louisville Ridge intersects with the arc. All of the centers contain calderas or caldera-like structures, as well as multiple cones, domes, fissure ridges, and vent fields. All show signs of recent eruptive and current hydrothermal activity. There are strong structural controls on edifice location, with cones and fissure ridges typically associated with faulting parallel to the regional $12°strike of the arc front. Several of the calderas are ellipsoidal, orientated northwest-southeast in the general direction of least compressive stress. Sampled volcanic rocks, representing the most recently erupted lavas, are all low-K tholeiites. Two of the centers, Gamble and Rakahore, yielded only highsilica dacite to rhyolite (69-74 wt% silica), whereas two others, Monowai and ''V,'' yielded only basalt to andesite (48-63 wt% silica). Mineral assemblages are plagioclasepyroxene dominated, with accessory Fe-Ti oxides, apatite, olivine, and quartz/tridymite/ cristobalite, typical of dry volcanic arc systems. Hornblende occurs only in a felsitic rhyolite from Hinepuia volcanic center, and zircon is absent. Glass contents range to 57% in basalts-andesites (mean 20%), and 97% in andesites-rhyolites (mean 59%) and other quench textures, including swallow-tailed, plumose, or dendritic crystal forms and crystallites, are common. Most lavas are highly vesicular ( 63%; mean 28%) and have low volatile contents (mostly <2 wt%) which, together with the occurrence of tridymite or cristobalite, indicates explosive eruption and rapid cooling. Exceptions are rocks from ''U'' volcanic center, which have low vesicularity and low glass contents across a wide compositional range, indicating effusive eruption. Disequilibrium mineral textures, the frequent occurrence of xenoliths and xenocrysts, and macroscopic evidence for magma mingling indicate that many of the lavas are hybrids, having resided only a short time in upper crustal reservoirs prior to eruption. Silicic magmas are major components of NKST arc volcanism and caldera formation is the dominant eruptive style. The scale of silicic magmatism is in marked contrast to the dominant basaltic-andesitic magmatism in the southern Kermadec arc. With evidence from other arcs, silicic magmatism is now recognized as a major feature of intraoceanic arcs globally.

The Leyva Canyon Member of the Rawls Formation is a sequence of Oligocene (27.3±27.1 Ma) silicic lava, tuff, and volcaniclastic rock that comprise a trachytic shield volcano in the central Bofecillos Mountains of Big Bend Ranch State Park, Texas. This silicic unit developed within a volcanic ®eld that was otherwise dominated by silica-undersaturated, ma®c to intermediate lava. Quartz trachyte to low-silica rhyolite of the Leyva Canyon volcano appears to be the result of magma mixing between mantle-derived, alkalic ma®c magmas and peraluminous crustal melt (,40% crustal input), followed by ,65% fractional crystallization. The parental ma®c component was probably similar to silica-undersaturated, ma®c lavas of the Rawls Formation. Peraluminous, A-type high-silica rhyolite represents the earliest-erupted lavas of the Leyva Canyon volcano and is unrelated to quartz trachyte and low-silica rhyolite via fractional crystallization. The high-silica rhyolite provides evidence for an episode of crustal melting beneath the Leyva Canyon volcano.

Icelandic threespine sticklebacks show parallel sympatric morphological differences related to different substrate habitats in four Icelandic lakes. The level of morphological diversification varies among the lakes, ranging from a population with a wide morphological distribution to a population with clear resource morphs, where morphological diversification was reflected in diet differences. These differences in morphological divergence are closely related to the differences in the ecological surroundings of each population. This appears to be resource polymorphism, which may lead to population differentiation and speciation. Trophically related sexual dimorphism was also common in these sticklebacks, which is possibly the result of sexual selection or habitat segregation by the sexes. 0

Mt. Merapi, Indonesia, is one of the most active and dangerous volcanoes in the Torrid Zone. This volcano has erupted frequently and has produced pyroclastic flows following the collapse of the summit lava dome. We used Synthetic Aperture Radar (SAR) data acquired by JERS-1 and RADARSAT-1 satellites from April 1996 to July 2006 to clarify the distribution patterns of the pyroclastic flow deposits. The extent of the deposits, termed P-zones, was accurately extracted by ratio operation and low-level feature extraction from SAR intensity images. These images highlighted temporal changes of the distribution area, perimeter, flow distance, included angle, and collapse direction. To validate the image-processing results, reflectance spectra of the rock samples collected after the eruption in June 2006 were measured in a laboratory. The reflectance spectra of all samples showed similar characteristics to the reference spectra, which were derived from atmospheric correction of Hyperion sensor image data covering the lava dome at the summit. Therefore, P-zones were confirmed to be the pyroclastic flow deposits originating from destruction of the lava dome at the summit. The image-processing results clarified that the extent of the distribution areas, perimeter, flow distances, and included angle of the P-zones were variable among the eruptions, while the collapse direction had a constant pattern. The collapse pattern followed a clockwise change from the south toward the west. By comparing the ratio maps of Bouguer gravity anomaly data in two periods, the change was interpreted to originate from the inclination of the conduit and the formation of shallow and deep magma reservoirs.

Volcanic fields in the Pannonian Basin, Western Hungary, comprise several Mio/Pliocene volcaniclastic successions that are penetrated by numerous mafic intrusions. Peperite formed where intrusive and extrusive basaltic magma mingled with tuff, lapilli-tuff, and non-volcanic siliciclastic sediments within vent zones. Peperite is more common in the Pannonian Basin than generally realised and may be also important in other settings where sediment sequences accumulate during active volcanism. Hajagos-hegy, an erosional remnant of a maar volcano, was subsequently occupied by a lava lake that interacted with unconsolidated sediments in the maar basin and formed both blocky and globular peperite. Similar peperite developed in Kissomlyó, a small tuff ring remnant, where dykes invaded lake sediments that formed within a tuff ring. Lava foot peperite from both Hajagos-hegy and Kissomlyó were formed when small lava flows travelled over wet sediments in craters of phreatomagmatic volcanoes. At Ság-hegy, a large phreatomagmatic volcanic complex, peperite formed along the margin of a coherent intrusion. All peperite in this study could be described as globular or blocky peperite. Globular and blocky types in the studied fields occur together regardless of the host sediment.

This paper summarizes the information on the geology and natural resources of the Jordan Badia Research and Development Programme. The research focused on the issue of the environment in arid lands as an aid to provide practical options for sustainable development. This paper presents results of field studies in the following areas related to the sustainable development of the Safawi area in the northern Jordan Badia; geomorphology, including landform, soil, lands, processes and hazards, geology and physical resources and surface water hydrology. Tertiary-Quaternary continental basalt flows and tuffs cover approximately 11 000 km 2 , the majority of the Safawi area. In addition to extensive basalt lava flows, the programme area includes a variety of geological outcrops and potential sources of economic products that include the following: Tuff/Scoria, Zeolite/Olivine, Porcellanite, potential sources of aggregate/ construction materials, ornamental stone, building stone, basalt for manufacturing of rock wool, and materials suitable for producing lightweight aggregate. The whole of the eastern Badia exhibits major Key words Arid lands 7 Sustainable development 7 Natural resources 7 Management 7 Geological setting 7 Surficial geology 7 Land systems 7 Landsat images 7 Surface water hydrology 7 Drainage network 7 Field experiments 7 Infiltration characteristics

Volcanic records of excursional geomagnetic field behavior, in particular paleointensity estimates, are fragmentary for the Pleistocene. The West Eifel volcanic field is unique in that 12 of 66 measured lava flow sites record Virtual Geomagnetic Poles (VGPs) clustered between 34-45 • N latitude and 30-50 • E longitude over the Middle East and Southeast Asia. Paleointensity determinations reveal that 13 of 37 lavas erupted during times when the ambient field was weak. Specifically, results on nine transitionally magnetized and four normally magnetized lavas indicate paleofield intensities less than 30 T associated with virtual dipole moments (VDMs) <4 × 10 22 Am 2 [Schnepp, E., Hradetzky, H., 1994. Combined paleointensity and 40 Ar/ 39 Ar age spectrum data from volcanic rocks of the West Eifel field (Germany): evidence for an early Brunhes geomagnetic excursion. J. Geophys. Res 99, 9061-9076]. Until now, the age of these lava flows has been known only from imprecise 40 Ar/ 39 Ar dating that implied acquisition of magnetic remanence between about 570 and 450 ka. Thus, they have been interpreted to record a single, but poorly defined, excursion in the lower Brunhes Chron. To incorporate these paleofield data into the global high-resolution Geomagnetic Instability Time Scale (GITS), we have determined precise ages of groundmass from 12 excursional and 7 normally magnetized lava flows using the 40 Ar/ 39 Ar incremental heating method. Unspiked K-Ar age determinations from two excursional samples are indistinguishable from their 40 Ar/ 39 Ar results. Ages of the excursional lava flows fall into five groups at 722 ± 38, 626 ± 24, 578 ± 8, 555 ± 4, and 528 ± 16 ka (±2 analytical uncertainties, relative to 1.194 Ma Alder Creek sanidine). The group of three excursional flows with an age of 578 ± 8 ka correspond temporally with lava flow sequences on Tahiti and La Palma that record the Big Lost excursion at 579 ± 6 ka. Eight other excursional lavas erupted from 722 to 528 ka correlate with less well-defined excursions or paleointensity minima differentially expressed in marine sediment records. Our findings that at least four, and perhaps five, temporally distinct excursions are recorded between 722 and 528 ka further suggest that each weakening of the dynamo during this period was associated with demise of the axial dipole. The VGPs produced during these excursions are found to be dispersed longitudinally across Eurasia and are remarkably similar to those associated with the calculated south VGPs at West Eifel for the non-axial dipole (NAD) field during the 20th century. A simple model in which the axial dipole repeatedly collapses leaving behind a residual NAD field that is largely held by stationary sources, probably in the lowermost mantle, provides an explanation for the recurrent excursional behavior during this ∼200 kyr period. (B.S. Singer). which for brief, ca. 1-10 kyr, periods differ from the Geocentric Axial Dipole (GAD) and lie outside the range of expected secular variation . Despite skepticism about the veracity of excursions and their use as stratigraphic markers , improved sampling of marine sediments deposited at high rates and precise geochronology applied to both sediments (astrochronology) and lava flows ( 40 Ar/ 39 Ar dating) has led to broad acceptance that many globally expressed excursions punctuate the Brunhes and Matuyama polarity chrons, 0031-9201/$ -see front matter

The Jalisco Block of western Mexico has undergone uplift in the Tertiary, in response to subduction tectonics. The Atenguillo River, interior to the Jalisco Block, has incised the bedrock units of the Jalisco Block, including Cretaceous ash flow tuff, granite, as well as younger volcanic lava flows. To study incision rates, knickpoint propagation, and the uplift rate of the region samples from nine different points along the Atenguillo channel were collected for 36Cl exposure age dating. Exposure ages along the length of the channel are high near the head of the basin where the river meanders in a broad plain. Ages are younger at the knickpoints and downstream where the river cuts deeply and forms a canyon. Incision rates measured at different points along the channel also correlate with channel slope and age. Low incision rates are measured in the oldest part of the channel near the head (station B; 2.5 mm/year), and just above the knickpoints (station C; 0.6 mm/year and station G; 1.4 mm/year). The incision rates are highest just below the knickpoints (station F; 2.4 mm/year) and farther downstream (stations H and I; 5.6 and 2.9 mm/year, respectively). The high incision rates can be attributed to subduction-related uplift of the Jalisco Block. Other features attributable to uplift are emergent paleoshorelines and uplifted marine sediments along the coast; and relatively lower incision rates were measured north of the Jalisco Block.

UAVs have become a useful tool for natural hazard monitoring. In volcanic areas, they allow wider observations of the eruptive behaviour, with no risk for the operator. The SfM technique enables obtaining orthoimages of lava flows and a DEM in a short time. These data are also useful to estimate lava flow volumes and the mass output rate characterizing an eruption. We present the results of ten UAV surveys made during and after the 30 May-6 June 2019 eruption of Etna volcano, projecting the data in a time context back until 1999. Orthoimages taken on different days allowed monitoring the morpho-structural evolution of the fissures, capturing the lava flows propagation and the accumulation of pyroclastic deposits. From 1999 to 2018, there were nine flank-eruptions and dozens of summiteruptions, which for graphic simplicity have been grouped by year in the map. The resulting map represents the most updated of the recent lava flows of Etna.