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  • Open access
  • 65 Reads
Estimating Source Apportionment of Heavy Metals Contamination in Surface Soil based on Positive Matrix Factorization (PMF) model around Cerrito Blanco in San Luis Potosi, Mexico

In recent decades, heavy metal contamination in soils has received a significant concern on a global scale. Quantitative apportionment of heavy metal sources in the surface soil throughout extensive regions is a perplexing task. This study indicated a receptor model to evaluate the heavy metal concentrations of various sources for the soil and the related contamination impacts. In this study, the surface soil at the Cerrito Blanco in San Luis Potosi, Mexico was chosen as the case study location to reveal the potential pollution sources of heavy metals. The research suggested the combined use of the positive matrix factorization (PMF) model for quantitative assessment of contamination sources and spatial distribution techniques for the conception of pollution sources, which forms the foundation for later soil contamination control and treatment. Throughout the study region, a total of thirty-nine samples of surface soil were collected. However, the mean concentration levels in the soils of Co, Cr, Cu, Ni, and Pb were lower than the permissible standards for soils. But it may be concluded that heavy metals have been contaminated in the surface soil since the mean concentration levels of As and Cd was higher than their permissible standard values by around 5.43 and 1.19 times, respectively. The PMF findings demonstrate that four major diverse sources of heavy metals in this study area's soils were natural, past mining activities, groundwater, and human activities. The concentrations of heavy metals in surface soils were considerably influenced by natural activities, which were generally the main factors. The spatial distribution of soil contamination for heavy metals was also mapped using the Geographic Information System (GIS) technique. As a result, more focus will be required to assess the heavy metal contamination of soils in regions that have had increasing economic growth and prosperity, such as Mexico.

  • Open access
  • 69 Reads
C-factor estimate for soil loss equations using transformation function (Near, Gaussian and Symmetric Linear) and remote sensing data

The study proposes a methodology to calculate the C-factor using remote sensing data: NDVI from LANDSAT image and MAPBIOMAS Land Use (LU) classification to Atibaia river watershed, Brazil, to improve the estimation of risk of soil loss using equations such as USLE and RUSLE. The methodology follows the procedures: first the NDVI was calculated, then the resulting image was rescaled to the range 0 to 1, applying the Near, Gaussian and Symmetric Linear transformation functions, with value below threshold 1, value above threshold 0 and scale 1 in the Rescale by function tool. Among the three models presented the Symmetric Linear model showed the best results for the distribution of C-factor values between the LU classes, while in the Gaussian model the same value was recorded, 0.70, for the Pasture and Rocky Outcrop classes and the average of the values was low 0.22 (Near) and 0.31 (Gaussian).

  • Open access
  • 95 Reads
Tajogaite 2021 eruption (La Palma, Canary Islands, Spain): an exceptional volcanic heritage to develop geotourism
Published: 30 November 2022 by MDPI in The 4th International Electronic Conference on Geosciences session Geoheritage

In the Canary Islands, sixteen historical eruptions have been documented in Lanzarote, Tenerife, El Hierro, and La Palma. The latest eruption, the Tajogaite eruption, occurred in 2021 in La Palma and the richness and diversity of natural and cultural heritage associated with this eruption can be a valuable resource for attracting visitors and tourists. The main aim of this work is to select Sites of Geo-Tourist Interest (SGIs) in order to create geo-itineraries. The methodology used is based on fieldworks and drone flight videos and photos taken during and after the eruption. Sixteen SGIs have been selected and studied. Eleven sites represent geoheritage of the Tajogaite eruption and seven sites are related to the surrounding natural and rural landscapes. In the near future, geo-itineraries (for in-person and virtual visits) will be created for visitors to La Palma and for the interested online audience.

  • Open access
  • 39 Reads
Geosites as Educational Key-Elements For Sustainability: The UNESCO Global Geoparks Model
Published: 30 November 2022 by MDPI in The 4th International Electronic Conference on Geosciences session Geoheritage

Geosites, or commonly called places of geological interest, have gained notoriety nowadays, positioning themselves as one of the most important resources in educational strategies for earth and environmental sciences. The possibility of observing the results of the different geological processes, morphologies, or minerals in situ helps us to understand how our planet works and how we, as a society, have taken advantage of its elements to progress in all areas of daily life. Their particularity and, above all, its variability, make them unique places that range from outcrops to mining complexes or outstanding viewpoints where we can learn about the message that the landscape conveys. For this reason, geosites are an incredible opportunity to learn about geolosciences, but also about history, traditions and everything related to the territory in which they are located. The UNESCO Global Geoparks (UGGps) are an international example of how to craft a sustainable development strategy focused on the educational potential of geosites. Complementing them with interpretation centers, information panels, QR codes and specialized guides, these territories have come to be considered as benchmarks within the so-called sustainable tourism, transforming the land into authentic open-air educational museums. Following a personal style and defending the appellation of origin, the UGGps create an exceptional model based on educational foundations that aims to bring the territory closer to the greatest number of people possible.

  • Open access
  • 37 Reads
Valuing Geodiversity in Patagonia Verde: A Fundamental Pillar for Developing a Future Geopark
Published: 30 November 2022 by MDPI in The 4th International Electronic Conference on Geosciences session Geoheritage

91 geological sites of scientific, tourist and educational interest were inventoried, following a survey under the project “Development of geotourism products in the tourist destination Patagonia Verde”. This project was developed between 2017 and 2019 to promote the values of geodiversity of the Patagonia Verde (southern Chile) territory and its sustainable use in tourism. A quantitative assessment of the sites supported the identification of management categories and the proposal of different action plans for the sustainable management of the identified geoheritage resources. Most sites can be used in education and geotourism initiatives and support the establishment and consolidation of the Patagonia Verde Geopark project.

  • Open access
  • 34 Reads
Geodiversity and Its Implication to Geoconservation of the Youngest Eruptive Sites of Western Samoa
Published: 30 November 2022 by MDPI in The 4th International Electronic Conference on Geosciences session Geoheritage

Western Samoa experienced its latest volcanic eruption between 1905 and 1911 that produced a complex scoria and lava spatter cone and an extensive lava field that destroyed Sale’aula village near the Pacific coast. This eruption referred to as the Matavanu eruption and it provided pahoehoe type lava flows with superbly preserved surface textures, tumuli, and some littoral explosion craters in its distal lava field. The unique nature of the location made it to be selected as one of the FIRST 100 UNESCO Global Geosites in 2022. The region has been under investigation to document the geoheritage elements of the location, estimate its geodiversity and explore the potential to develop a geopark together with local communities. All this work intends to provide a firm knowledge base to identify effective geoconservation strategies. While the youngest eruptive products after over 100 years of revegetation are restricted in a coastal zone, previous research demonstrated that other young volcanic eruptions also took place in northern Savai’i in 1760 and 1902. Here we provide further data based on systematic evaluation of SENTINEL satellite imagery in combination with ALOS-PALSAR digital terrain model-based calculation of morphometric elements to demonstrate the young volcanic landscape in northern Savai’i has great volcanic geodiversity and the entire region should be considered under specific geoconservation strategies. The young volcanic landforms of scoria cones in the high-altitude regions of the island alongside with extensive and commonly tube-fed lava flows invaded the northern region of Savai’i also pose volcanic hazard to the region hence volcanic geoheritage can be the core element to enforce strong community volcanic hazard resilience. The newly proposed Samoa Geopark Project is the perfect avenue to achieve this.

  • Open access
  • 31 Reads
Geodiversity elements of a young fissure system as an immediate precursory event of the youngest fissure-fed eruption within the Arxan UNESCO Global Geopark, Inner Mongolia in NE China
Published: 02 December 2022 by MDPI in The 4th International Electronic Conference on Geosciences session Geoheritage

The Arxan-Chaihe Volcanic Field (ACVF) is a Pliocene to Recent intracontinental monogenetic volcanic field. Within the ACVF are preserved at least 47 vents in a ~2000 km2 area, forming two major NE-SW trending structural elements. The youngest eruptions took place about 2000 BP, forming two distinct complex scoria and lava spatter cone systems emitting low viscosity lava that invaded the paleo-Halaha River tributary forming pahoehoe flow fields. This lava field forms the backbone of the geoheritage values of the Arxan UNESCO Global Geopark. The lava flow fields were believed to be almost exclusively sourced from a single vent complex around the Yanshan – Gaoshan region, however recent study has revealed the flow field is a result of complex eruptions with an early phase from the nearby Dahei Gou vent complex. Here we provide evidence, based on SENTILEN satellite imagery, ALOS- PALSAR-derived digital terrain model analysis, and direct field observations that an even earlier fissure-fed eruption created another complex. This can be seen as a smaller lava flow field in the western side of the main flow field. The Dichi Lake is an iconic geosite of the geopark. It is a maar crater formed by a single explosion through an earlier lava field erupted from a network of fissures ~2.5 km-long following a NE-SW trend. The Dichi Lake geosite provides an ideal example demonstrating the effect of fissures opening in water-saturated lowlands resulting in phreatomagmatic eruptions. Moreover, our findings suggests that the youngest eruption in this region had at least three phases, probably not more than few decades apart along a 15 km-long fissure network propagated from the SW to NE. We propose Dichi Lake as the center of a geoheritage precinct, providing a hub of knowledge dissemination highlighting fissure eruptions as a key type of volcanic hazard to be taken seriously in management of the Geopark.

  • Open access
  • 23 Reads
Micromorphs: Response of the Ammonite Fauna during the Toarcian Oceanic Anoxic Event (T-OAE) in the Es-Saffeh Mountains (Tiaret, Western Algeria)

The paleontological analysis of the fauna of ammonites collected in the marl-limestone series of the Pliensbachian and The Toarcian of the Es-Saffeh Mountains (Tiaret, western Algeria) brings new data to the Oceanic Anoxic Event of the lower Toarcian (T-OAE). During this time interval, hypoxia is characterized by a significant disturbance of the global carbon cycle marked by a negatve excursion of the isotope δ13C, δ18O and a increase in organic carbon content (TOC). Benthic life almost completely disappears and microfauna (foraminifera) is absent, it should however be pointed out that the few specimens of small size (swarf forms) collected in the marly levels and well identified (ammonites), attributed to the microshell forms; can be interpreted as a response to the conditions of the reducing environment during the Lower Toarcian, particularly at the end of the Polymorphum Zone and the beginning of the Levisoni Zone.

  • Open access
  • 45 Reads
Effects of driftwood on erosion of debris flows

Debris-flow Flume experiments of deposition and fan formation have been mostly conducted over hard non-porous plane. However, the surface a debris-flow travels on is influencing the dynamics of the flow and the deposition process as it has been shown recently. We have argued that (1) water exchange occurs with the surface and (2) material exchange (erosion and deposition) is also occurring in the deposition area. Continuing from this set of experiments, we are now attempting to clarify the role of debris in the debris-flow, one of them which are often neglected is wood debris.

In the present contribution, the authors attempted to quantify the role of wood debris on deposition and deposits in a controlled environment. For the present experiment, we used a flume with a reception pan that is 185.6 cm length x 95.6 cm width, with walls 26.2 cm high. The channel is 400 cm long, 25.0 cm high, and 18.5 cm wide. Repeating earlier experiments without wood debris, the receiving pan was spread with a 1-2 cm thick sediment layer. In the channel, a set of wood debris were erected. From this setup, the authors ran multiple experiment setups with 5 repeats of the same experiment each time. Using video-camera recording of the flow, photogrammetry of the deposits. The authors also collected sediment samples over the surface to compare porosity and density of the deposit.

The results have shown that the wood debris increased the variability in density and porosity in the deposit, regardless of the starting setting with woods, in comparison to “no-wood” patterns. The authors argue that this is due to mixing with the wood debris during deposition, modifying the semi-linear energy loss on a typical deposition fan. The mixing is further complicated as wood debris collided with each other based on the video analysis, so that the variability is not only due to the characteristics of the debris, but how it interacted with other debris and with the sediments. The authors further argue that the difference in erosion of the substratum, with wood-debris rich experiments tended to erode less, may be due to reduced momentum due to the energy consumed to transport the wood debris.

  • Open access
  • 77 Reads
Ionospheric effects of natural hazards in geophysics: from single examples to statistical studies applied to M5.5+ earthquakes

Geophysical natural hazards, such as earthquakes and volcano eruptions, can have catastrophic effects on the population depending on the location and quality of construction. From the geophysical point of view, several aspects are still debated in the preparation phase of such events. In particular, several theories proposed that prior to the earthquake and volcano eruption, the releases of gas, fluids or charged particle from the lithosphere (e.g., the fault for the earthquake) could create some effects on the atmosphere and ionosphere. In this work, several single examples will be shown of possible candidates of pre-earthquake ionospheric disturbances recorded by the China National Space Administration (in partnership with the Italian Space Agency) China Seismo Electromagnetic Satellite (CSES) or European Space Agency Swarm constellation. The examples will show anomalous ionospheric status in terms of magnetic disturbances or increase of electron density before earthquakes like Mw=7.1 Ridgecrest (US) 2019 or during the large recent volcano eruption of Hunga Tonga-Hunga Ha’Apai of last 15 January 2022. In these cases, some couplings between the lithosphere and ionosphere are proposed. Finally, verifying if such ionospheric disturbances proceeded for “chance” or are really linked to the incoming event is a crucial point. For this purpose, we performed worldwide statistical studies, not only supporting the recurrence of such phenomena for about 15% of M5.5+ shallow earthquakes but also showing a link between the magnitude of the upcoming seismic events and the pre-earthquake anticipation time. Furthermore, we also show the influence of the location ( sea or land) on the frequency of the ionospheric electromagnetic disturbance.