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Karoly Nemeth works as a Professor in Geology at the School of Agriculture and Environment of the Massey University, Palmerston North, New Zealand. He received his Ph.D. degree in geology from the Otago University, Dunedin, New Zealand, in 2001. Nemeth’s areas of expertise include sedimentology, physical volcanology, magma-water interaction research, volcanic hazard studies, volcano geology, geoheritage studies and geoconservation research. Nemeth’s research is centered on understanding monogenetic volcanism and volcanic field evolution. Nemeth works on research on understanding the phreatomagmatic eruption styles and volcanic field evolution in New Zealand, Idaho (USA), Argentina, Chile, China, Colombia, Hungary, Libya, Mexico, Saudi Arabia, SW Pacific, Japan and Korea.
The Arxan-Chaihe Volcanic Field, Inner Mongolia, NE China is a Pleistocene to Recent volcanic field still considered to be active. In this chapter we provide an update of current volcanological research conducted in the last four years to describe the volcanic architecture of the identified vents, their eruptive history and potential volcanic hazards. Here we provide an evidence-based summary of the most common volcanic eruption styles and types the field experienced in its evolution. The volcanic field is strongly controlled by older structural elements of the region. Hence most of the volcanoes of the field are fissure-controlled, fissure-aligned and erupted in Hawaiian to Strombolian-style creating lava spatter and scoria cone cone chains. One of the largest and most complex volcano of the field (Tongxin) experienced a violent phreatomagmatic explosive phase creating a maar in an intra-mountain basin, while the youngest known eruptions formed a triple vent set (Yanshan) that reached violent Strombolian phases and created an extensive ash and lapilli plains in the surrounding areas. This complex vent system also emitted voluminous lava flows that change the landscape by damming fluival networks, providing a volcanological paradise for the recently established Arxan UNESCO GLobal Geopark.
Boxin Li; Károly Németh; Julie Palmer; Alan Palmer; Jing Wu; Jonathan Procter; Jiaqi Liu. Basic Volcanic Elements of the Arxan-Chaihe Volcanic Field, Inner Mongolia, NE China. Updates in Volcanology - Transdisciplinary Nature of Volcano Science 2021, 1 .
AMA StyleBoxin Li, Károly Németh, Julie Palmer, Alan Palmer, Jing Wu, Jonathan Procter, Jiaqi Liu. Basic Volcanic Elements of the Arxan-Chaihe Volcanic Field, Inner Mongolia, NE China. Updates in Volcanology - Transdisciplinary Nature of Volcano Science. 2021; ():1.
Chicago/Turabian StyleBoxin Li; Károly Németh; Julie Palmer; Alan Palmer; Jing Wu; Jonathan Procter; Jiaqi Liu. 2021. "Basic Volcanic Elements of the Arxan-Chaihe Volcanic Field, Inner Mongolia, NE China." Updates in Volcanology - Transdisciplinary Nature of Volcano Science , no. : 1.
Open access peer-reviewed chapter
Károly Németh. Introductory Chapter: Updates in Volcanology - Transdisciplinary Nature of Volcano Science. Updates in Volcanology - Transdisciplinary Nature of Volcano Science 2021, 1 .
AMA StyleKároly Németh. Introductory Chapter: Updates in Volcanology - Transdisciplinary Nature of Volcano Science. Updates in Volcanology - Transdisciplinary Nature of Volcano Science. 2021; ():1.
Chicago/Turabian StyleKároly Németh. 2021. "Introductory Chapter: Updates in Volcanology - Transdisciplinary Nature of Volcano Science." Updates in Volcanology - Transdisciplinary Nature of Volcano Science , no. : 1.
Geoheritage is an important aspect in developing workable strategies for natural hazard resilience. This is reflected in the UNESCO IGCP Project (# 692. Geoheritage for Geohazard Resilience) that continues to successfully develop global awareness of the multifaced aspects of geoheritage research. Geohazards form a great variety of natural phenomena that should be properly identified, and their importance communicated to all levels of society. This is especially the case in urban areas such as Auckland. The largest socio-economic urban center in New Zealand, Auckland faces potential volcanic hazards as it sits on an active Quaternary monogenetic volcanic field. Individual volcanic geosites of young eruptive products are considered to form the foundation of community outreach demonstrating causes and consequences of volcanism associated volcanism. However, in recent decades, rapid urban development has increased demand for raw materials and encroached on natural sites which would be ideal for such outreach. The dramatic loss of volcanic geoheritage of Auckland is alarming. Here we demonstrate that abandoned quarry sites (e.g., Wiri Mountain) could be used as key locations to serve these goals. We contrast the reality that Auckland sites are underutilized and fast diminishing, with positive examples known from similar but older volcanic regions, such as the Mio/Pliocene Bakony–Balaton UNESCO Global Geopark in Hungary.
Károly Németh; Ilmars Gravis; Boglárka Németh. Dilemma of Geoconservation of Monogenetic Volcanic Sites under Fast Urbanization and Infrastructure Developments with Special Relevance to the Auckland Volcanic Field, New Zealand. Sustainability 2021, 13, 6549 .
AMA StyleKároly Németh, Ilmars Gravis, Boglárka Németh. Dilemma of Geoconservation of Monogenetic Volcanic Sites under Fast Urbanization and Infrastructure Developments with Special Relevance to the Auckland Volcanic Field, New Zealand. Sustainability. 2021; 13 (12):6549.
Chicago/Turabian StyleKároly Németh; Ilmars Gravis; Boglárka Németh. 2021. "Dilemma of Geoconservation of Monogenetic Volcanic Sites under Fast Urbanization and Infrastructure Developments with Special Relevance to the Auckland Volcanic Field, New Zealand." Sustainability 13, no. 12: 6549.
Both Savai’i Island and Upolu Island of Samoa are home to numerous potential geosites that could form the basis of geopark projects at a range of scales from local, regional, or global. During the Samoa Geoparks Project Phase 1, intensive research identified Samoa’s geoheritage values, resulting in the selection of the island of Savai’i as a location for development of geosite inventories, using a first-order approach to create a scientific basis for future geoheritage, geoconservation, and geotourism ventures. The rationale behind this decision was based on the size of the island; the geodiverse and largely untouched landscapes with high geodiversity values; and superbly exposed young volcanic features that are relatively accessible. Most of these volcanic features derived from Holocene and even historical volcanic activity. Within the potential areas of geosites, volcanic features currently utilized as tourist attractions (mataaga in Samoan) are mostly associated with living cultural activities in terms of traditional stories, myth, and place names. These geoheritage components are a very significant part of the Samoa Geoparks Project in general. Workshop and training for further development of the Samoa Geoparks Project are recommended in this study to co-design and co-develop the geopark concept with local communities working in collaboration with geoscience experts. The role of external geoscientists has been redefined as facilitators of participatory methods using iterative, step-by-step processes, where each facet of the geopark is co-produced through truly inclusive methods and frameworks.
Aleni Fepuleai; Károly Németh; Tolu Muliaina. Geopark Impact for the Resilience of Communities in Samoa, SW Pacific. Geoheritage 2021, 13, 1 -23.
AMA StyleAleni Fepuleai, Károly Németh, Tolu Muliaina. Geopark Impact for the Resilience of Communities in Samoa, SW Pacific. Geoheritage. 2021; 13 (3):1-23.
Chicago/Turabian StyleAleni Fepuleai; Károly Németh; Tolu Muliaina. 2021. "Geopark Impact for the Resilience of Communities in Samoa, SW Pacific." Geoheritage 13, no. 3: 1-23.
Ordination methods are used in ecological multivariate statistics in order to reduce the number of dimensions and arrange individual variables along environmental variables. Geoheritage designation is a new challenge for conservation planning. Quantification of geoheritage to date is used explicitly for site selection, however, it also carries significant potential to be one of the indicators of sustainable development that is delivered through geosystem services. In order to achieve such a dominant position, geoheritage needs to be included in the business as usual model of conservation planning. Questions about the quantification process that have typically been addressed in geoheritage studies can be answered more directly by their relationships to world development indicators. We aim to relate the major informative geoheritage practices to underlying trends of successful geoheritage implementation through statistical analysis of countries with the highest trackable geoheritage interest. Correspondence analysis (CA) was used to obtain information on how certain indicators bundle together. Multiple correspondence analysis (MCA) was used to detect sets of factors to determine positive geoheritage conservation outcomes. The analysis resulted in ordination diagrams that visualize correlations among determinant variables translated to links between socio-economic background and geoheritage conservation outcomes. Indicators derived from geoheritage-related academic activity and world development metrics show a shift from significant Earth science output toward disciplines of strong international agreement such as tourism, sustainability and biodiversity. Identifying contributing factors to conservation-related decisions helps experts to tailor their proposals for required evidence-based quantification reports and reinforce the scientific significance of geoheritage.
Boglárka Németh; Károly Németh; Jon Procter. Informed Geoheritage Conservation: Determinant Analysis Based on Bibliometric and Sustainability Indicators Using Ordination Techniques. Land 2021, 10, 539 .
AMA StyleBoglárka Németh, Károly Németh, Jon Procter. Informed Geoheritage Conservation: Determinant Analysis Based on Bibliometric and Sustainability Indicators Using Ordination Techniques. Land. 2021; 10 (5):539.
Chicago/Turabian StyleBoglárka Németh; Károly Németh; Jon Procter. 2021. "Informed Geoheritage Conservation: Determinant Analysis Based on Bibliometric and Sustainability Indicators Using Ordination Techniques." Land 10, no. 5: 539.
Geoheritage is an emerging research subject with increasing global interest to define, characterize and quantify it in diverse geological and geomorphological settings. As being a new research subject there are great variety of conceptual approaches to do its definition and quantification. Geoheritage conservation is in the process of establishing a common ground that become necessary in the transnational collaboration for a sustainable future. Geoheritage conservation generates ever increasing number of scientific publications based on heterogenous evaluation methods with limited consensus within the field. The produced material, also part of various Big Data repositories, conceals valuable patterns and information on the level of agreement and the solution to draw the line for the acceptable level of subjectivity. Analysing bibliometric data of scientific publication appear in accessible global data bases (e.g. Web of Science) broken down to country levels allow us to find potential indicators for geoheritage designation. Finding determinants that positively influences decision makers and end users within the conservation arena helps geoscientists to achieve policy impact and increase the number of recognised and protected geological and geomorphological sites. Multiple Correspondence Analysis was used to detect and explore relationships between population, land, tourism, protected areas and bibliometric variables. The result revealed very important links between the socio-economic background and geoheritage conservation outcomes. The fact that there was no one major determinant found that would affect geoheritage conservation globally means that a common ground awaits to be established on which countries can build upon with the unique and special values local communities have to contribute toward geoheritage conservation.
The research is aligned with the goals of the “Geoheritage for Resilience” UNESCO IGPC project 692 program.
Boglárka Németh; Károly Németh. Determinants of geoheritage conservation: Multiple correspondence analysis to explore interrelations between socio-economic and bibliometric data. 2021, 1 .
AMA StyleBoglárka Németh, Károly Németh. Determinants of geoheritage conservation: Multiple correspondence analysis to explore interrelations between socio-economic and bibliometric data. . 2021; ():1.
Chicago/Turabian StyleBoglárka Németh; Károly Németh. 2021. "Determinants of geoheritage conservation: Multiple correspondence analysis to explore interrelations between socio-economic and bibliometric data." , no. : 1.
Mátyás Hencz; Tamás Biró; Zoltán Cseri; Dávid Karátson; Emő Márton; Károly Németh; Alexandru Szakács; Zoltán Pécskay; István János Kovács. A Lower Miocene pyroclastic-fall deposit from the Bükk Foreland Volcanic Area, Northern Hungary: Clues for an eastward-located source. Geologica Carpathica 2021, 72, 1 .
AMA StyleMátyás Hencz, Tamás Biró, Zoltán Cseri, Dávid Karátson, Emő Márton, Károly Németh, Alexandru Szakács, Zoltán Pécskay, István János Kovács. A Lower Miocene pyroclastic-fall deposit from the Bükk Foreland Volcanic Area, Northern Hungary: Clues for an eastward-located source. Geologica Carpathica. 2021; 72 (1):1.
Chicago/Turabian StyleMátyás Hencz; Tamás Biró; Zoltán Cseri; Dávid Karátson; Emő Márton; Károly Németh; Alexandru Szakács; Zoltán Pécskay; István János Kovács. 2021. "A Lower Miocene pyroclastic-fall deposit from the Bükk Foreland Volcanic Area, Northern Hungary: Clues for an eastward-located source." Geologica Carpathica 72, no. 1: 1.
Maar volcanoes are monogenetic landforms whose craters cut below the pre-eruptive surface and are surrounded by a tephra ring. Both the maar crater and the surrounding tephra rim deposits are typically formed due to magma–water explosive interactions. Northern Chile is located in the Central Volcanic Zone of the Andes where, in literature, 14 maars have been recognized as parasite (6) and individual (8) volcanoes. Amongst these individual maars, 3 of them, namely the Tilocálar Sur, Cerro Tujle, and Cerro Overo volcanoes, are not related to calderas and were emplaced < 1 Ma ago by magmatic explosive-effusive and phreatomagmatic eruptions. Based on the evolution and control of the volcanic eruptive styles of these three maars, which have been determined in previous research through fieldwork, stratigraphic, morphometric, textural (density and vesicularity), petrographic, and geochemical analyses, a set of key features that favor a prediction of the emplacement location of maar volcanoes in Central Andes, northern Chile are proposed. The set of features that permit and favor the growth mechanisms for maar formations corresponds to (i) a compressive tectonic setting (e.g., ridge structures), (ii) groundwater recharge (e.g., snowmelt and seasonal rainfall), (iii) the lithological setting (e.g., layers of low permeability), (iv) the presence of aquifer and/or endorheic basins (e.g., lakes or salars), and (v) a period of stress relaxation that permits magma ascent to the surface in volcanically active areas. Considering these characteristics, it is possible to identify places where phreatomagmatic eruption can occur. If the magma ascent flux is lower than the groundwater flux, this can lead to a phreatomagmatic eruption because of groundwater coming into contact with the magma. These eruptive features evidence internal—and external—factors that play an essential role in the transition from explosive-effusive magmatic to phreatomagmatic volcanic eruption styles during the same eruptive period that is one of the biggest challenges in volcanic hazard evaluations. Although, in this contribution, a set of features that permit and favor the growth mechanisms for a prediction of the emplacement location of maars in northern Chile is proposed, these considerations could also be applied to identify potential locations in other parts of the world where magma–water interaction eruption could occur. Therefore, this approach could be useful in the prediction of hydromagmatic volcanic eruptions and, thus, in mitigating the impact of volcanic hazard for the inhabitants of the surrounding areas.
Gabriel Ureta; Károly Németh; Felipe Aguilera; Rodrigo González. Features That Favor the Prediction of the Emplacement Location of Maar Volcanoes: A Case Study in the Central Andes, Northern Chile. Geosciences 2020, 10, 507 .
AMA StyleGabriel Ureta, Károly Németh, Felipe Aguilera, Rodrigo González. Features That Favor the Prediction of the Emplacement Location of Maar Volcanoes: A Case Study in the Central Andes, Northern Chile. Geosciences. 2020; 10 (12):507.
Chicago/Turabian StyleGabriel Ureta; Károly Németh; Felipe Aguilera; Rodrigo González. 2020. "Features That Favor the Prediction of the Emplacement Location of Maar Volcanoes: A Case Study in the Central Andes, Northern Chile." Geosciences 10, no. 12: 507.
Cenozoic geological evolution of New Zealand centres around the formation of Zealandia, a new continent that became detached from the eastern margin of Gondwana around 105 Ma. Spreading opened the Tasman Sea leaving a fragment of continental lithosphere, largely submerged, in the SW Pacific. Throughout the Cenozoic history, volcanism became an integral part of Zealandia. Continental lithosphere provided the basement for the volcanism, both onshore and offshore. Monogenetic volcanism was common throughout the Cenozoic. The availability of water was ubiquitous through surface water bodies (oceans and lakes) and various other terrestrial hydrous systems provided by the humid temperate climate of Zealandia. Hydrovolcanism, both explosive and non-explosive, has played a significant role in Zealandia's volcanic history resulting in volcano mega- architecture involving edifice geology and volcanic hazards. However, hydrovolcanism has commonly been overlooked in Zealandia's monogenetic volcanism context. Cenozoic monogenetic fields of Zealandia provide a unique laboratory and comparative analogy for other volcanic fields on Earth that are associated with low-lying terrestrial settings or shallow marine environments in a humid temperate climate.
Károly Németh; Szabolcs Kósik. The role of hydrovolcanism in the formation of the Cenozoic monogenetic volcanic fields of Zealandia. New Zealand Journal of Geology and Geophysics 2020, 63, 1 -26.
AMA StyleKároly Németh, Szabolcs Kósik. The role of hydrovolcanism in the formation of the Cenozoic monogenetic volcanic fields of Zealandia. New Zealand Journal of Geology and Geophysics. 2020; 63 (4):1-26.
Chicago/Turabian StyleKároly Németh; Szabolcs Kósik. 2020. "The role of hydrovolcanism in the formation of the Cenozoic monogenetic volcanic fields of Zealandia." New Zealand Journal of Geology and Geophysics 63, no. 4: 1-26.
Geoheritage is now a globally recognized natural conservation strategy built on a research and science-based framework. We suggest that to date in New Zealand, mainstream approaches to conservation, protection, and tourism have poorly served our unique geoheritage landscapes and features. The two locations presented as cases in this paper represent geoheritage and cultural values unique to New Zealand due to its dynamic geological history and cultural history represented in the archaeological record. In this paper, we demonstrate the potential for community-led development utilizing internationally recognized best practices. This in turn will provide a foundation for low-impact and sustainable tourism, education, and training opportunities of benefit to local, regional, and national communities. New Zealand has recently joined the global geoheritage trend through the UNESCO Global Geoparks Programme, with the first application for geopark designation in this country currently under review. In this paper, we define geoheritage and associated concepts and demonstrate their potential role in tourism development and research, based on international best-practice methodologies and frameworks. Here, we investigate current issues relating to geoheritage and geotourism in New Zealand. We discuss a current lack of coherent protective legislation relating to geoheritage features and landscapes, demonstrated by the conflict between development and protection being played out at four geologically significant sites at two locations in New Zealand. Geotourism potential of the Ōtuataua Stonefields Historic Reserve in South Auckland has been the subject of research, with guided tours undertaken on an ad hoc basis. A community group is currently campaigning against a proposed housing development adjacent to the Historic Reserve and facilitating research and community engagement with the cultural and geological history of the area. We present the nearby Māngere Mountain Education Centre as a model on which to base further geoheritage development within the area. At the centre, low-impact non-invasive methods and technologies are used, thereby supporting and facilitating sustainable education and tourism ventures in collaboration with the local community and tangata whenua (indigenous people of the land). In the South Island of New Zealand, investigations over the last decade have revealed Foulden Maar as one of the most significant palaeogeographical and palaeoecological sites in the Southern Hemisphere. The maar in Central Otago is the preserved remnant of a crater lake formed by explosive phreatomagmatic volcanic eruptions about 23 million years ago. Diatomite deposits accumulated in the maar crater contain a rich and significant fossil record of the Miocene in New Zealand and the wider Southern Hemisphere. We use recent developments in the case of Foulden Maar to highlight the lack of a national policy or legislation relating specifically to significant fossil or geoheritage sites on private land. The nearby Vanished-World Fossil Museum is a highly successful community-based venture highlighting the geoheritage of the area in an accessible and engaging manner, built on 17 years of largely voluntary contributions in collaboration with the University of Otago.
Ilmars Gravis; Károly Németh; Chris Twemlow; Boglárka Németh. The Case for Community-Led Geoheritage and Geoconservation Ventures in Māngere, South Auckland, and Central Otago, New Zealand. Geoheritage 2020, 12, 1 -24.
AMA StyleIlmars Gravis, Károly Németh, Chris Twemlow, Boglárka Németh. The Case for Community-Led Geoheritage and Geoconservation Ventures in Māngere, South Auckland, and Central Otago, New Zealand. Geoheritage. 2020; 12 (1):1-24.
Chicago/Turabian StyleIlmars Gravis; Károly Németh; Chris Twemlow; Boglárka Németh. 2020. "The Case for Community-Led Geoheritage and Geoconservation Ventures in Māngere, South Auckland, and Central Otago, New Zealand." Geoheritage 12, no. 1: 1-24.
Hydrovolcanism is a type of volcanism where magma and water interact either explosively or non-explosively. The less frequently used term, hydromagmatism, includes all the processes responsible for magma and water interaction in a magmatic system. Hydrovolcanism is commonly used as a synonym for phreatomagmatism. However, in recent years phreatomagmatism appears more in association with volcanic eruptions that occur in shallow subaqueous or terrestrial settings and commonly involves molten fuel-coolant interaction (MFCI) driven processes. Here a revised and reviewed classification scheme is suggested on the basis of the geo-environment in which the magma-water interaction takes place and the explosivity plus mode of energy transfer required to generate kinetic energy to produce pyroclasts. Over the past decade researchers have focused on the role hydrovolcanism/phreatomagmatism plays in the formation of maar craters, the evolution of diatremes and the signatures of magma—water interaction in the geological record. In the past five years, lithofacies-characterization is the most common approach to studying hydrovolcanism. By far mafic monogenetic volcanic fields generated the greatest number of research results. Significant knowledge gaps are identified, especially in developing tools to identify the textural signatures hydrovolcanism leave behind on eruptive products and exploring the role of hydrovolcanism in the growth of intermediate and silicic small volume volcanoes.
Károly Németh; Szabolcs Kósik. Review of Explosive Hydrovolcanism. Geosciences 2020, 10, 44 .
AMA StyleKároly Németh, Szabolcs Kósik. Review of Explosive Hydrovolcanism. Geosciences. 2020; 10 (2):44.
Chicago/Turabian StyleKároly Németh; Szabolcs Kósik. 2020. "Review of Explosive Hydrovolcanism." Geosciences 10, no. 2: 44.
Wudalianchi volcanic field (WDLC) is one of the youngest intracontinental monogenetic volcanic fields in China. The 1719–1721 CE Laoheishan-Huoshaoshan eruption, and the 1776 CE Laoheishan eruption are the latest eruptions in WDLC based on the local historical records. However, most of the recent explosive eruptive products around WDLC are attributed to the 1719–1721 CE Laoheishan-Huoshaoshan eruption while less attentions were paid on the 1776 CE Laoheishan eruption. There are two types of scoria fall deposits around Laoheishan volcano, i.e. the upper light grey high vesicular scoria deposit (US) and below dark low vesicular scoria deposit (BS). Most of the glass shards from US exhibit >4% Na2O while BS show 5%) content with trachyandesitic to tephriphonolitic in composition that can be clearly distinguished from those from other nearby volcanic regions, such as Nuomin (~150 km to Nangelaqiushan lake (NGLQ)), Arxan-Chaihe (~450 km to NGLQ), Longgang (~700 km to NGLQ) and Jingbohu (~550 km to NGLQ). A cryptotephra layer is clearly revealed as a distinct peak in magnetic susceptibility measurements from NGLQ ~ 8 km northwest to Laoheishan volcano. Glass composition of the cryptotephra layer recorded in NGLQ is similar to the proximal US around Laoheishan volcano. On basis of historical records and field observations, we ascribed US to the 1776 CE Laoheishan eruption and BS to the 1719–1721 CE Laoheishan-Huoshaoshan eruption. Consequently, historical records assigned a precise age (1776 CE) for the tephra recorded in NGLQ, and thus can be used to refine the age model of these lacustrine sediments.
Chunqing Sun; Károly Németh; Tao Zhan; Haitao You; Guoqiang Chu; Jiaqi Liu. Tephra evidence for the most recent eruption of Laoheishan volcano, Wudalianchi volcanic field, northeast China. Journal of Volcanology and Geothermal Research 2019, 383, 103 -111.
AMA StyleChunqing Sun, Károly Németh, Tao Zhan, Haitao You, Guoqiang Chu, Jiaqi Liu. Tephra evidence for the most recent eruption of Laoheishan volcano, Wudalianchi volcanic field, northeast China. Journal of Volcanology and Geothermal Research. 2019; 383 ():103-111.
Chicago/Turabian StyleChunqing Sun; Károly Németh; Tao Zhan; Haitao You; Guoqiang Chu; Jiaqi Liu. 2019. "Tephra evidence for the most recent eruption of Laoheishan volcano, Wudalianchi volcanic field, northeast China." Journal of Volcanology and Geothermal Research 383, no. : 103-111.
Explosive phreatomagmatic eruption is one of the most hazardous eruption styles, particularly in basaltic systems, as the instability of the conduit system can result in a sudden and unexpected shift of eruption style from a mild effusion of lavas to violently explosive activity. The geological investigations on the phreatomagmatic activities in the 7th Century, Suoana-Kazahaya eruption (SKE) of Miyakejima, reveal that the drop of magmatic overpressure in conduit and the distribution of groundwater controlled the occurrence of phreatomagmatic explosion. The “dry” magmatic eruption in the initial phase of the SKE indicates that the positive overpressure of magma in the propagating feeder dike prevents the invasion of external groundwater into the conduit. Explosive phreatomagmatic eruption occurred at the later phase of the SKE from the vents in the higher elevation. The drop of magmatic overpressure in the upper part of the feeder dike caused by the downslope propagation of the eruption fissure allowed groundwater inflow to the still hot and molten feeder dikes. The limited distribution of phreatomagmatic activities indicated the development of shallow groundwater, hosted in the porous pyroclastic deposits within a basin of less-permeable older edifice. As shifts of eruption style from initial magmatic to later phreatomagmatic explosive eruption style in the top of mafic volcanoes are globally observed in many mafic volcanic systems, such as Kilauea and Mt. Etna, this is probably a far more common eruption mechanism, than previously thought, and hence it needs to be considered in volcanic hazard scenario descriptions. The spatial distributions of phreatomagmatic activities in the SKE suggest that the detection of buried caldera structure in a volcanic edifice can indicate a potential site for phreatomagmatic explosion. The monitoring of the propagation of eruption fissure and drops of magmatic pressure and flux can indicate the potential of the phreatomagmatic explosion by the invasion of groundwater into the hot conduit.
Nobuo Geshi; Károly Németh; Rina Noguchi; Teruki Oikawa. Shift from magmatic to phreatomagmatic explosions controlled by the lateral evolution of a feeder dike in the Suoana-Kazahaya eruption, Miyakejima Volcano, Japan. Earth and Planetary Science Letters 2019, 511, 177 -189.
AMA StyleNobuo Geshi, Károly Németh, Rina Noguchi, Teruki Oikawa. Shift from magmatic to phreatomagmatic explosions controlled by the lateral evolution of a feeder dike in the Suoana-Kazahaya eruption, Miyakejima Volcano, Japan. Earth and Planetary Science Letters. 2019; 511 ():177-189.
Chicago/Turabian StyleNobuo Geshi; Károly Németh; Rina Noguchi; Teruki Oikawa. 2019. "Shift from magmatic to phreatomagmatic explosions controlled by the lateral evolution of a feeder dike in the Suoana-Kazahaya eruption, Miyakejima Volcano, Japan." Earth and Planetary Science Letters 511, no. : 177-189.
Crystals within erupted volcanic rocks record geochemical and textural signatures during magmatic evolution prior to the onset of eruptions. Growth times of microlites can be derived through Crystal Size Distribution (CSD) analysis combined with well-constrained microlite growth rates, yielding petrologically-determined magma ascent timescales. Our newly developed, machine learning image processing scheme allows for the rapid generation of CSD, saving many hours of processing time, which previously involved hand-drawing the outer margins of crystals. For the present study, we examined a range of andesitic tephras from the Tongariro Volcanic Centre, New Zealand. A total of 228 plagioclase and pyroxene microlites CSDs were generated from individual tephra shards. All combined pyroxene and plagioclase microlite CSDs exhibit concave-up shapes, and similar intercepts and slopes at the smallest sizes. This implies similar growth durations of the smallest microlites of 15±9 to 28±15 (2σ) hours, regardless of the eruptive style or source, using an orthopyroxene microlite growth rate constrained from one of the samples. The orthopyroxene thermometer and the plagioclase hygrometer reveal the magmas were erupted at ~ 1079 to 1149 (±39 SEE), and H2O contents ranging from 0-0.4 to 0-1.7 wt.% (95% confidence maxima). In the absence of CO2, these results indicate shallow H2O exsolution pressures of < 240 bars, using a recent H2O-CO2 solubility model. Given the microlite residence times, shallow H2O exsolution driving microlite growth is inconsistent with the explosivity of the eruptions. Instead, our data suggest that the melts either carried large amounts of CO2, triggering earlier degassing of volatiles including H2O, or that microlite crystallisation began prior to degassing. Ongoing work investigates the H2O and CO2 contents hosted by melt inclusions in phenocrysts and microphenocrysts in these tephras to provide constraints on magma ascent rates, with implications for hazard characterization and mitigation.
Charline Lormand; Georg Zellmer; Geoff Kilgour; Yoshiyuki Iizuka; Stuart Mead; Naoya Sakamoto; Karoly Nemeth; Alan Palmer; Anja Moebis; Takeshi Kuritani; Hisayoshi Yurimoto. Microlite Size Distributions and P-T-t-x (H2O) constraints of Central Plateau tephras, New Zealand: implications for magma ascent processes of explosive eruptions. 2019, 1 .
AMA StyleCharline Lormand, Georg Zellmer, Geoff Kilgour, Yoshiyuki Iizuka, Stuart Mead, Naoya Sakamoto, Karoly Nemeth, Alan Palmer, Anja Moebis, Takeshi Kuritani, Hisayoshi Yurimoto. Microlite Size Distributions and P-T-t-x (H2O) constraints of Central Plateau tephras, New Zealand: implications for magma ascent processes of explosive eruptions. . 2019; ():1.
Chicago/Turabian StyleCharline Lormand; Georg Zellmer; Geoff Kilgour; Yoshiyuki Iizuka; Stuart Mead; Naoya Sakamoto; Karoly Nemeth; Alan Palmer; Anja Moebis; Takeshi Kuritani; Hisayoshi Yurimoto. 2019. "Microlite Size Distributions and P-T-t-x (H2O) constraints of Central Plateau tephras, New Zealand: implications for magma ascent processes of explosive eruptions." , no. : 1.
Crystals within volcanic rocks record geochemical and textural signatures during magmatic evolution before eruption. Clues to this magmatic history can be examined using crystal size distribution (CSD) studies. The analysis of CSDs is a standard petrological tool, but laborious due to manual hand-drawing of crystal margins. The trainable Weka segmentation (TWS) plugin in ImageJ is a promising alternative. It uses machine learning and image segmentation to classify an image. We recorded back-scattered electron (BSE) images of three volcanic samples with different crystallinity (35, 50 and ≥85 vol. %), using scanning electron microscopes (SEM) of variable image resolutions, which we then tested using TWS. Crystal measurements obtained from the automatically segmented images are compared with those of the manual segmentation. Samples up to 50 vol. % crystallinity are successfully segmented using TWS. Segmentation at significantly higher crystallinities fails, as crystal boundaries cannot be distinguished. Accuracy performance tests for the TWS classifiers yield high F-scores (>0.930), hence, TWS is a successful and fast computing tool for outlining crystals from BSE images of glassy rocks. Finally, reliable CSD’s can be derived using a low-cost desktop SEM, paving the way for a wide range of research to take advantage of this new petrological method.
Charline Lormand; Georg F. Zellmer; Károly Németh; Geoff Kilgour; Stuart Mead; Alan S. Palmer; Naoya Sakamoto; Hisayoshi Yurimoto; Anja Moebis. Weka Trainable Segmentation Plugin in ImageJ: A Semi-Automatic Tool Applied to Crystal Size Distributions of Microlites in Volcanic Rocks. Microscopy and Microanalysis 2018, 24, 667 -675.
AMA StyleCharline Lormand, Georg F. Zellmer, Károly Németh, Geoff Kilgour, Stuart Mead, Alan S. Palmer, Naoya Sakamoto, Hisayoshi Yurimoto, Anja Moebis. Weka Trainable Segmentation Plugin in ImageJ: A Semi-Automatic Tool Applied to Crystal Size Distributions of Microlites in Volcanic Rocks. Microscopy and Microanalysis. 2018; 24 (6):667-675.
Chicago/Turabian StyleCharline Lormand; Georg F. Zellmer; Károly Németh; Geoff Kilgour; Stuart Mead; Alan S. Palmer; Naoya Sakamoto; Hisayoshi Yurimoto; Anja Moebis. 2018. "Weka Trainable Segmentation Plugin in ImageJ: A Semi-Automatic Tool Applied to Crystal Size Distributions of Microlites in Volcanic Rocks." Microscopy and Microanalysis 24, no. 6: 667-675.
Karoly Nemeth; Chunqing Sun; Jing Wu; Patrick Rioual; Zhengfu Guo; Guoqiang Chu. Preface. Journal of Volcanology and Geothermal Research 2018, 383, 1 .
AMA StyleKaroly Nemeth, Chunqing Sun, Jing Wu, Patrick Rioual, Zhengfu Guo, Guoqiang Chu. Preface. Journal of Volcanology and Geothermal Research. 2018; 383 ():1.
Chicago/Turabian StyleKaroly Nemeth; Chunqing Sun; Jing Wu; Patrick Rioual; Zhengfu Guo; Guoqiang Chu. 2018. "Preface." Journal of Volcanology and Geothermal Research 383, no. : 1.
Geological mapping in volcanic terrains is a challenging task as there needs to be input from various geologists' groups and only limited, often ambiguous guidelines exist. Volcanoes and volcanic successions are in many ways viewed and treated differently than normal sedimentary successions. Volcanic systems are very much a part of the normal sedimentary environment and as such need to integrated into the stratigraphic framework of the enclosing deposits. Most volcanoes supply large volumes of material (pyroclasts) into the sedimentary system. The type and style of eruption determines the time frame of the process, while the type of volcano defines the interaction between volcano and background sedimentation (e.g. monogenetic versus polygenetic volcanic systems). A sound lithostratigraphic framework for mapping geological units in volcanic terrains should also adopt the latest developments in volcanology and understanding of volcanic systems. The lithostratigraphic classification needs to define the mapping unit and apply it to the 1) proximal to distal volcanic facies, 2) eruption styles and their temporal changes, and 3) mode of pyroclast transportation (i.e. fallout versus pyroclastic density current). Differentiation of syn- and post-eruption re-sedimentation, during either within- or between eruptive phases, will determine the most useful stratigraphic nomenclature system to apply to the volcanic units. The approach to geological mapping in ancient and modern volcanic terrains can be different but the same basic stratigraphic principles and classification apply. The purpose of the geological mapping project, whether it be in ancient or modern volcanic systems, will define the style and scale of mapping. The type of output depends upon the objectives and available resources, including the volcanological experience of the mapping team. Here we provide some insight from a New Zealand perspective to geological mapping on active volcanic terrains in a convergent plate margin.
Károly Németh; Julie Palmer. Geological mapping of volcanic terrains: Discussion on concepts, facies models, scales, and resolutions from New Zealand perspective. Journal of Volcanology and Geothermal Research 2018, 385, 27 -45.
AMA StyleKároly Németh, Julie Palmer. Geological mapping of volcanic terrains: Discussion on concepts, facies models, scales, and resolutions from New Zealand perspective. Journal of Volcanology and Geothermal Research. 2018; 385 ():27-45.
Chicago/Turabian StyleKároly Németh; Julie Palmer. 2018. "Geological mapping of volcanic terrains: Discussion on concepts, facies models, scales, and resolutions from New Zealand perspective." Journal of Volcanology and Geothermal Research 385, no. : 27-45.
We propose a global framework for the Earth system to facilitate communication between the geoscience community, the public and policy makers. Geoscience research aims to understand the history and evolution of the Earth system. This combines the non-living and living parts of the Earth, especially through interactions of the lithosphere, biosphere and atmosphere as well as the other parts of the system, such as the asthenosphere, core and extraterrestrial influences. Such research considers a system that spans scales from microscopic (micrometer scale) to megascopic (many 1000 s of km scale), and from milliseconds to millions of years. To connect different parts of this immense system, we habitually use a wide range of ad hoc geological frameworks, systems and geological environment models, where different processes and features operate and combine. In consequence, one way to judge the significance of our work, and to increase its value, is to assess how the elements studied are integrated within the whole Earth system. This allows us to see what implications any study has for this greater Earth system. To do this successfully, our research needs a standard global framework to assess a study's relevance. However, such a global framework does not formally exist, and so this article looks at existing examples and proposes one that can systematically place research into a global geological context. This proposed framework has the advantage of being useful for communicating geological processes to other disciplines, and can be used for any type of Earth (or planetary) environment. This framework is a fundamental tool for geoscience communication and for outreach, especially through geological heritage (geoheritage). Geoheritage concerns the valuing and protection of geoscience and geological sites, and is a vital tool for communicating geoscience. It can be used to communicate our knowledge of global change, providing, through landscapes and outcrops, a story that renders the concepts and advances of geoscience accessible. Like our basic research, the concept of geoheritage evolves as our understanding of the Earth progresses, and these dual changes can be explained with the global framework. Geoheritage is a global activity and it needs a global framework to put sites into context. A revision of the UNESCO geological thematic studies was called for by the World Heritage Committee in 2014 (decision: 38 COM 8B.11), and this can be done with the input from the full geoscience community using this global geological framework. Thus, for research, geoscience policy and for geoheritage, a global framework is now needed. The proposed framework can place any site in its geological environment, related to its lithospheric plate tectonic setting and its history. The framework has a solid-earth bias (lithosphere), but includes all other spheres, such as the biosphere and anthropogenic activity. Extraterrestrial influences, like solar variations and impacts are included. The framework is phenomenological, due to the necessity of grouping the features that we see, but these phenomena provide evidence of processes that we cannot see. The basic format is a table, a sketch of the Earth and a system diagram, three complementary and most powerful ways of depicting a system. A timeline, or stratigraphic column can be included, to show the evolution of geological history, and the table can be used as a ‘game board’ where one site migrates across from one set of conditions to another over time. The global framework allows any research site, area or subject to be set in the Earth's system, in a way that gives it context, allows comparisons and provides significance. We suggest that it can be a template for an internationally accepted version used to consolidate the necessary geoscience – geoheritage link and promote outreach.
Benjamin Van Wyk De Vries; Paul Byrne; Audray Delcamp; Pall Einarson; Oğuz Göğüş; Marie-Noëlle Guilbaud; Miruts Hagos; Szabolcs Harangi; Dougal Jerram; Liviu Matenco; Sophie Mossoux; Karoly Nemeth; Mehran Maghsoudi; Michael S. Petronis; Vladislav Rapprich; William I. Rose; Erika Vye. A global framework for the Earth: putting geological sciences in context. Global and Planetary Change 2018, 171, 293 -321.
AMA StyleBenjamin Van Wyk De Vries, Paul Byrne, Audray Delcamp, Pall Einarson, Oğuz Göğüş, Marie-Noëlle Guilbaud, Miruts Hagos, Szabolcs Harangi, Dougal Jerram, Liviu Matenco, Sophie Mossoux, Karoly Nemeth, Mehran Maghsoudi, Michael S. Petronis, Vladislav Rapprich, William I. Rose, Erika Vye. A global framework for the Earth: putting geological sciences in context. Global and Planetary Change. 2018; 171 ():293-321.
Chicago/Turabian StyleBenjamin Van Wyk De Vries; Paul Byrne; Audray Delcamp; Pall Einarson; Oğuz Göğüş; Marie-Noëlle Guilbaud; Miruts Hagos; Szabolcs Harangi; Dougal Jerram; Liviu Matenco; Sophie Mossoux; Karoly Nemeth; Mehran Maghsoudi; Michael S. Petronis; Vladislav Rapprich; William I. Rose; Erika Vye. 2018. "A global framework for the Earth: putting geological sciences in context." Global and Planetary Change 171, no. : 293-321.
Landslides and rockfalls on volcanic islands in tropical climate are characteristic landscape shaping features. Their common formation poses potential hazard for island communities; hence, understanding their formation and recognition on modern landscapes are vital element of educating local communities and providing mitigation strategies for future events. As landslides and rockfalls are continuously shaping tropical islands’ landscapes, they contribute significantly to the volcanic geoheritage of those islands. Rockfall and landslide hazards are commonly associated with the Fagaloa Formation and Salani Formations of Western Samoa in the SW Pacific. Four case studies (Mauga-o-Fao, Mauga-o-Vaea, Fagaloa Bay, and Leagi’agi Hill) are reported here, based on highly populated areas which are predicted to be vulnerable in generating rockfalls and landslides in the future. Field observations and interpretation of aerial photographs and satellite images were used to identify landslide and rockfall hazards in the region. The lack of records and previous studies related to rockfalls and landslides in the region is the major challenge for this investigation. Commonly, rockfall and landslide scenarios in Western Samoa are associated with the presence of high angle faults, highly weathered, extensively jointed, and fractured rocks. Surface and groundwater could expand the size of the joints, and existing fault scarps trigger the rock face to become more unstable by losing its support. There are two networks of jointing patterns commonly occurring in both old (3 Ma to 800 ka) and young (200 ka to 3 ka) volcanic rock formations: parallel and perpendicular with lava flow axis. These joint networks would increase the instability of tabular lava flows especially nearby to fault scarps and thick columnar jointed lavas. It is suggested that the major faults on the main islands almost running perpendicular to the central volcanic rift (elongated north east to south west) could be other main drivers of the rockfall and landslide hazards in the region.
Aleni Fepuleai; Károly Németh. Volcanic Geoheritage of Landslides and Rockfalls on a Tropical Ocean Island (Western Samoa, SW Pacific). Geoheritage 2018, 11, 577 -596.
AMA StyleAleni Fepuleai, Károly Németh. Volcanic Geoheritage of Landslides and Rockfalls on a Tropical Ocean Island (Western Samoa, SW Pacific). Geoheritage. 2018; 11 (2):577-596.
Chicago/Turabian StyleAleni Fepuleai; Károly Németh. 2018. "Volcanic Geoheritage of Landslides and Rockfalls on a Tropical Ocean Island (Western Samoa, SW Pacific)." Geoheritage 11, no. 2: 577-596.
Deception Island (Antarctica) is the southernmost island of the South Shetland Archipelago in the South Atlantic. Volcanic activity since the eighteenth century, along with the latest volcanic unrest episodes in the twentieth and twenty-first centuries, demonstrates that the volcanic system is still active and that future eruptions are likely. Despite its remote location, the South Shetland Islands are an important touristic destination during the austral summer. In addition, they host several research stations and three summer field camps. Deception Island is characterised by a Quaternary caldera system with a post-caldera succession and is considered to be part of an active, dispersed (monogenetic), volcanic field. Historical post-caldera volcanism on Deception Island involves monogenetic small-volume (VEI 2–3) eruptions such forming cones and various types of hydrovolcanic edifices. The scientific stations on the island were destroyed, or severely damaged, during the eruptions in 1967, 1969, and 1970 mainly due to explosive activity triggered by the interaction of rising (or erupting) magma with surface water, shallow groundwater, and ice. We conducted a detailed revision (field petrology and geochemistry) of the historical hydrovolcanic post-caldera eruptions of Deception Island with the aim to understand the dynamics of magma-water interaction, as well as characterise the most likely eruptive scenarios from future eruptions. We specifically focused on the Crimson Hill (estimated age between 1825 and 1829), and Kroner Lake (estimated age between 1829 and 1912) eruptions and 1967, 1969, and 1970 events by describing the eruption mechanisms related to the island’s hydrovolcanic activity. Data suggest that the main hazards posed by volcanism on the island are due to fallout, ballistic blocks and bombs, and subordinate, dilute PDCs. In addition, Deception Island can be divided into five areas of expected activity due to magma-water interaction, providing additional data for correct hazard assessment on the island.
Dario Pedrazzi; Károly Németh; Adelina Geyer; Antonio M. Álvarez-Valero; Gerardo Aguirre-Díaz; Stefania Bartolini. Historic hydrovolcanism at Deception Island (Antarctica): implications for eruption hazards. Bulletin of Volcanology 2017, 80, 11 .
AMA StyleDario Pedrazzi, Károly Németh, Adelina Geyer, Antonio M. Álvarez-Valero, Gerardo Aguirre-Díaz, Stefania Bartolini. Historic hydrovolcanism at Deception Island (Antarctica): implications for eruption hazards. Bulletin of Volcanology. 2017; 80 (1):11.
Chicago/Turabian StyleDario Pedrazzi; Károly Németh; Adelina Geyer; Antonio M. Álvarez-Valero; Gerardo Aguirre-Díaz; Stefania Bartolini. 2017. "Historic hydrovolcanism at Deception Island (Antarctica): implications for eruption hazards." Bulletin of Volcanology 80, no. 1: 11.