Volcanic Deposits Research Articles

Understanding the fracture-volcanism pattern: gravity and magnetic characterization of the Early Jurassic pull-apart structure in the Western Northpatagonian Region, Argentina

The Early Jurassic outcrops of the Río Negro Province provide a remarkable opportunity to evaluate the genetic significance of the potential anomalies related to the syn-rift structures. The Cañadón Chileno Complex pull-apart structure consists of two different areas, northern and southern, infilled with sedimentary and volcanic deposits. The residual gravity data indicate that the thicknesses vary significantly. The north area reaches 700 m, while the south has 500 m, which agrees with the on-site thicknesses. In addition, the 2D model indicates that the thicker sequence has a subcircular morphology coinciding with the ancient crater or diatreme structure location.The gravity and magnetic data reveal an array of positive and negative anomalies, providing comprehensive insights into the intricate configuration of the pull-apart structures. A remarkable attribute of the gravimetric and magnetic methods is their ability to identify volcanic structure's position linked to the pull-apart extension. In this sense, we can confidently assert that these volcanic structures form at the intersection of the complex's internal faults (in horsetail faults) and the eastern boundary of the pull-apart (sinistral strike-slip fault). The results show that the combined gravity and magnetic methods offer a workflow useable for understanding the behavior of sedimentary and volcanic interaction inside the pull-apart structures.

Assessment of indoor radon levels at multiple floors of an apartment building in the historic center of Rome (Italy): a comprehensive study

The urbanized area of Rome is largely built over volcanic deposits, characterized by a significant radionuclides content and consequently a high radon emanation potential. An accurate monitoring of workplaces and residential dwellings constitutes a first step towards mitigating the indoor radon exposure. Since radon diffusion dynamics involves complex interactions among many environmental parameters on different time scales, a proper assessment of radon concentration variations can be better achieved by means of active monitoring approaches. We present here the results of 1 year of continuous measurements conducted in six premises (five apartments and a basement) at different floors of the same building in the Esquilino district, in the historical center of Rome. Collecting annual series of radon concentration enables us to identify fluctuations over a seasonal scale, with radon generally decreasing in the warm season. The simultaneous tracking of different floors should cancel the influence of geogenic radon and of building characteristics like age, typology, and construction materials. While the basement shows the highest radon concentration, indicating a major contribution from the ground, we observe indoor radon levels comparable at all the upper floors, questioning the common belief that high-risk exposure be limited to the lowest storeys. The use of active devices makes it possible to discriminate between average indoor radon measured during the day and overnight, when residents are more likely to be at home. Our analysis provides the characterization of the dynamics of the gas emanation and transport inside the buildings and of its temporal fluctuations, in relation to the environmental and meteorological conditions. Since the experiment was performed in the Roman urban contest, we cannot ignore the specificity of the retrieved data, affected not only by endogenous factors like life habits relative to ventilation and conditioning of the apartments, but also by exogenous factors, among which the warmer microclimate compared to the surrounding suburban and rural areas, due to the effects of urbanization (urban heat island effect).

Insight on physical–mechanical properties of one-part alkali-activated materials based on volcanic deposits of Mt. Etna (Italy) and their durability against ageing tests

In recent years, there has been a growing interest in one-part alkali-activated materials, which utilize solid-form alkali activators, within the construction industry. This approach is becoming popular due to its simpler and safer application for cast-in-situ purposes, as compared to the conventional two-part method. At this purpose, we have pioneered the use of volcanic deposits of Mt. Etna volcano (Italy) as precursor for the synthesis of a unique one-part formulation. This was done to assess its performance against both traditional and two-part alkali-activated materials. The study employed a comprehensive range of investigative techniques including X-ray powder diffraction, Fourier transform infrared spectroscopy, hydric tests, mercury intrusion porosimetry, ultrasound, infrared thermography, spectrophotometry, contact angle measurements, uniaxial compressive strength tests, as well as durability tests by salt crystallization and freeze–thaw cycles. The key findings on the studied samples are as follows: i) small size of pores and slow absorption-drying cycles; ii) satisfying compactness and uniaxial compressive strengths for building and restoration interventions; iii) high hydrophily of the surfaces; iv) lower heating dispersion than traditional materials; v) significant damage at the end of the salt crystallization test; vi) excellent resistance to freeze–thaw cycles. These newly developed materials hold promises as environmentally friendly options for construction applications. They offer a simplified mixing process in contrast to the conventional two-part alkali-activated materials, thus providing an added advantage to this class of materials.

The characteristics of volcanic lithofacies and volcanic reservoirs in the Permian Jiamuhe Formation, Southern Zhongguai Rise, Junggar Basin, NW China

The southern Zhongguai Rise has gained wide attentions due to its commercial hydrocarbon discoveries from volcanic deposits in Jinlong Oilfield. The integrated analysis of geological and geophysical data assist in determination and depiction of volcanic lithology and volcanic facie, characterization of volcanic reservoirs as well as discussion of constrains on volcanic lithology/lithofacies. The conclusions suggest that two types of volcanic lithology, including volcaniclastic rocks and silicic moltenlava, can be identified based on cores. In addition, two types of volcanic lithofacies can be delineated according to cores and wireline responses. The explosive facies are mainly developed in early depositional period while the effusive facies are developed through depositional period. Furthermore, the reservoir space predominantly consists of pores and fractures according to thin sections. The physical property varies from time to time. That is, porosity distribution varies slightly. In contrast, permeability distribution varies significantly. The volcanic reservoirs can be generally attributed to high-porosity and low-permeability reservoirs no matter in volcaniclastic rocks or silicic molten lava. The volcanic lithofacies, facies distribution, diagenism and paleogeomorphology exserts controls on physical property and reservoir performance of volcanic reservoirs together.

Local sediment amendment can potentially increase barley yield and reduce the need for phosphorus fertilizer on acidic soils in Kenya

Soil acidification and low nutrient availability are two major challenges facing agriculture in most regions of East Africa, resulting in aluminum toxicity and poor crop yields. The amendment of local sediments to cropland can potentially alleviate these challenges, but responses are variable. In this study, we investigated the potential of two different local sediments influenced by volcanic deposits to increase soil pH, Si and P availability and reduce Al toxicity, thereby improve barley yield. Hence, a field experiment was established in Eldoret, Western Kenya, using 1% and 3% addition by weight of two sediments in barley cultivated plots. The Baringo 3% amendment significantly increased soil pH (from 4.7 to 7.0), the available P content (from 0.01 mg g−1 to 0.02 mg g−1) and decreased the Al availability (from 3.03 mg g−1–2.17 mg g−1). This resulted in a barley yield of 4.7 t/ha (+1061%). The Nakuru 3% and Baringo 1% amendments increased yield to 2–3 t/ha, while the Nakuru 1% did not significantly increase yield. These results highlight that, from a biophysical perspective, there are natural and local opportunities to reduce soil acidification and to partly replace mineral fertilizer, but its magnitude depends on the sediment and the amendment rate.

The Content Of Heavy Metal In Turmeric (Curcuma Domestica Val.) In The Volcanic Rocks Oligocene-Miocene Volcano, Biting Wonogiri, Central Java, Indonesia

The Biting Wonogiri area is an area composed of Oligocene-Miocene volcanic deposits and volcanic deposits from Lawu Volcano. The rocks in this area consist of pyroclastic rocks, volcanic breccia, and dacite intrusions. Residents in this area more commonly grow herbal plants such as turmeric. Turmeric plants are mostly planted on old volcanic rocks, namely the Oligocene-Miocene age. By studying the planting patterns of residents, an analysis was carried out regarding the heavy metal chemical elements contained in turmeric. The research methodology was carried out using geological mapping to determine the distribution of the rocks that make up the research area and AAS analysis (Atomic Absorption Spectroscopy). This AAS method is used to determine heavy metal content. The heavy metal elements analyzed in turmeric were Hg, Pb, As, Fe, Al, and Mn. From the analysis results it was found that the heavy metal elements Hg, Pb, and As had very low levels, namely around 0.005-0.400 mg/Kg. Meanwhile, the elements Al, Fe, and Mg have high contents. Turmeric grown on dacite and volcanic breccia has higher Al (622.3-1362.76 mg/Kg) and Fe (271.32-806.27 mg/Kg) content compared to turmeric planted on sedimentary rock. Meanwhile, the metal element Mn varies around 6.85-122.01 mg/Kg. By knowing the content of these Western metal elements, it is hoped that turmeric, which contains heavy metal elements, can be used as a superior herbal herbal medicine. These metal elements, which are very important nutrients, come from old volcanic rocks.

Mildly explosive eruptions at Martian low-shield volcanoes

AbstractOngoing acquisition of Martian surface imagery constantly provides new opportunities to reveal previously undiscovered small-scale volcanic landforms, yielding critical insights into volcanic processes, and challenging existing inferences. Here, using the most recent, high-resolution topographical data, we mapped the accumulation of pyroclastic deposits occurring along the margins of several volcanic vents. They share morphological similarities with terrestrial volcanic deposits attributed to low-intensity lava fountaining occurring during mild explosive activity. Our identified, explosive volcanic deposits are associated with late Amazonian volcanic activity in Tharsis. The identification of these very recent (<100 Ma) deposits across the entire Tharsis volcanic province needs reconciling with our current view of the evolution of explosive volcanism on Mars. We contend that these small volume landforms, produced by mildly explosive volcanic activity, need to be considered in models surrounding planet-scale magmatic evolution and atmospheric volatile budgets.

Situational Analysis of Groundwater Resources in Kenyan Drylands, Case study of Turkana County

Recent climate changes have increased the incidences of severe droughts and floods, which have increased the vulnerability of pastoralists in the Kenyan drylands. Thus, there is a need to carry out a situational analysis of groundwater as it is the main source of water which provides baseline information useful for planning Analysis of results indicates that Turkana County is dominated by shallow wells and boreholes with the shallowest wells located along the seasonal rivers and Lake Turkana. The borehole depth was found to range between 20 to 200m. Most of the boreholes located near Lake Turkana were shallower compared to those far away from the lake with a depth ranging between 0 to 52m. Most of the boreholes had a low yield that ranged between 1.2 to 4.6m3/hr be attributed to the basement rocks which are prevalent in the county and are classified as poor aquifers. The water points were mainly dense in urban areas, which was mainly the central region where the water demand was high and this was attributed to the high population. The groundwater levels occurred mostly at 13m indicating that Turkana County has mostly shallow aquifers that predominantly occurred along the river valleys and at the edge of the volcanic deposits. The groundwater quality is mainly saline as most of the boreholes had high TDS, EC and chloride levels. The presence of high fluoride levels indicates the presence of high volcanic rocks that have high fluoride ions that are largely prevalent in the study region. The Sulphate, Nitrite and Nitrate Levels in all the water samples analyzed were below the EU, WHO and KEBs standards indicating the low anthropogenic activities carried out in the drylands as most farmers are pastoralists. The most prevalent cation was sodium in some of the boreholes indicating why the groundwater was saline.

Tracking quartz and zircon provenance in sedimentary rocks using Ti distributions: Unlocking the volcanic-plutonic connection in old igneous systems

Although the relationship between silicic volcanic and plutonic rocks has been extensively studied, it remains controversial whether most plutons have volcanic counterparts and how the volcanic-to-plutonic ratio has evolved through time. This stems primarily from the scarcity of geologic examples with both volcanic and plutonic counterparts, especially in ancient terranes where volcanic deposits have likely been eroded. Here, we introduce a novel approach to identify remnant volcanic crystals in proximal siliciclastic/detrital rock formations. As most erupted crystals stop their growth before reaching the solidus, in contrast to plutonic crystals, the distribution of Ti (a proxy for temperature of crystallisation and/or magma evolution) in (weathering-resistant) quartz and zircon can help in identifying volcanic crystals in sedimentary rocks derived from supracrustal sources that have been completely eroded. Laser-ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses of quartz and zircon from volcanic and plutonic units that are known to be spatially and temporally related (from Southern Rocky Mountain Volcanic Field, Colorado, and Taupo Volcanic Zone, New Zealand) reveal that volcanic crystals have generally distinct distributions of, and on average higher Ti contents than, plutonic crystals. To further develop and test this methodology, we analysed samples from the 1.075 Ga Pikes Peak granite (CO, USA) and from the associated series of intra-granite sedimentary dikes that form part of the Cryogenian Period Tava sandstone. Blue band cathodoluminescence (CL) images can be used as a proxy for Ti-in-quartz. Our CL-screening method provides a statistically representative distribution of Ti contents in quartz crystals from individual thin sections. The Tava sandstone contains a higher concentration of high-Ti (and hence high-temperature) quartz and zircon grains than the average Pikes Peak batholith, interpreted as grains eroded from a no longer exposed, volcanic counterpart of the Pikes Peak magmatic system. Our study illustrates a means to test whether magmatic reservoirs that are now represented by crystallised ancient plutons once fed volcanic eruptions, and identifies a strategy for reconstructing volcanic-plutonic relationships, even when parts of the geological association have been eroded.

Interaction between basement detachment fault, rift onset unconformity, and overlying basin fills: An example from the Songliao basin of a Cretaceous active continental margin volcanic rift in northeast Asia

How does a giant rift basin begin? No precise examples describe this issue. Based on 7108 m of continuous coring data recovered from the whole stratigraphy of the Songliao Basin (SLB), an attempt has been made to answer this question. Through comprehensive geological, geochemical and seismic research it has been found that there is a triangular extensional domain (TED) beneath the sedimentary cover in the basement at the rift center, from where the initial rupture of the giant rift was created. The basement detachment fault (DF), rift onset unconformity (ROU), and overlying basin fills are interrelated elements of a sedimentary basin and are the key to interpreting the geological archives recorded in the basin. The interaction processes between them determine the location of the basin center and the style of basement subsidence, which reflect the tectonic properties of the basin. This interaction may have a coevolutionary relationship with the deep magmatic activities beneath the basin. The basement of a basin typically consists of a series of strata that the lower strata age older. The uppermost basement sequence of the Triassic in the SLB is particularly important for the overlying basin formation and evolution. The surface topography controlled the thickness of the overlying Cretaceous cover. An ROU and DF developed at the top and bottom of the Triassic, respectively.The long-term uplift, denudation, and subsequent volcanic deposition may be common features of an ROU in a volcanic rift basin. More so, DF is the controlling factor for basin subsidence in the syn-rift stage of basin evolution. The frequent intrusive association with graben faults suggests that sublithospheric mantle flow may affect the accommodation space of the overlying basin by cutting the basement blocks via feeder dykes and shaping the graben pattern on top of the basement.

Soil morphological characteristics in the active volcanic toposequence zone at Tangkuban Parahu volcano, Indonesia

Soil formation in volcanic terrains presents a significant challenge due to the diverse physical and chemical properties imparted by volcanic activity, which are not yet fully understood. This study investigates the unique morphological characteristics of soil profiles within crater topography sequences at the Tangkuban Parahu Volcano, Indonesia. To address this gap, five representative sample profiles (I, II, III, IV, V) were analyzed. The Ratu Crater pathway topography was characterized by steep to very steep slopes. Detailed analysis identified three predominant soil layers, each with distinct features such as color, texture, porosity, and chemical composition, reflecting different stages of soil formation. At the highest elevation near the crater rim, Profile V was composed mainly of volcanic ash, with a loose structure, high porosity, and acidic pH, indicative of recent volcanic deposits. Profile III, at intermediate elevations, consisted of highly weathered soil with sandy loam textures and clear layer demarcations, suggesting prolonged soil development and consolidation. Profile I, at the lowest elevation, featured loamy sand with significant weathering and organic matter incorporation, indicating advanced soil development stages. The findings underscore the impact of volcanic activity on soil morphology, revealing distinct layers that correlate with various ages and developmental stages. Understanding these processes can inform agricultural practices.

Hydrothermal calcite formation in Campi Flegrei caldera, Italy: unraveling carbon sink processes in alkaline volcanic systems

Understanding carbon dioxide emissions variability in volcanic regions is vital for detecting instabilities in the subvolcanic plumbing system, crucial for managing both volcanic and environmental risks. While changes in magmatic sources drive these variations, non-magmatic processes can complicate signal interpretation, especially in caldera environments. Here, geothermal systems can sequester CO2 within the bedrock through hydrothermal calcite precipitation, significantly impacting surface-level CO2 emissions. Unfortunately, few studies have explored this phenomenon, examining hydrothermal calcite origins and their effects on carbon balances and temporal gaseous patterns in active volcanic settings. Our study developed a specialized methodology for quantifying CO2 sequestered in hydrothermal calcites within alkaline caldera systems. We focused on analyzing hydrothermal calcite in lithics from volcanic deposits of eruptions of varying ages, Volcanic Explosivity Index (VEI), and eruptive vent locations to enhance the representativeness of the entire caldera bedrock. Unlike core samples from geothermal wells, which are infrequent and limited to specific depths, lithics can be easily collected, offering a comprehensive understanding of CO2 sequestration. Through extensive 3D textural characterization and isotopic investigations on hydrothermal calcite within lithic fragments from selected alkaline volcanic deposits in the Campi Flegrei caldera, our findings emphasized the significant influence of calcite sinks on the overall CO2 budget released by volcanoes throughout their evolution.

Comparison of the vs30 model and site class based on MASW, microtremor and N-SPT data in the Opak River Basin

Abstract The utilization of vs30 data offers numerous applications within the geotechnical field, with one of its primary applications being the determination of site class and the microzonation of site class. vs30 data can be acquired through various methods, including Multichannel Analysis of Surface Waves (MASW), microtremor measurements, and N-SPT data. This study seeks to compare vs30 data and site class criteria based on measurements obtained from MASW, microtremor, and N-SPT data in the Opak River Basin. For the vs30 data analysis, a total of 27 data points from MASW and microtremor measurements, along with 3 data points from N-SPT measurements, were employed. These measurements were conducted across various geological formations, encompassing the young volcanic deposits of Merapi Volcano, alluvial deposits, and the Nglanggran, Sentolo, Wonosari, and Semilir Formations. It is worth noting that all N-SPT data were specifically collected within the young volcanic deposits of the Merapi Volcano Formation. The results of this analysis revealed vs30 values ranging from 159 to 192 m/s for MASW measurements, 156 to 789 m/s for microtremor measurements, and 241 to 249 m/s for N-SPT measurements. In accordance with the SNI 1726-2019 site class criteria, the site classes determined based on vs30 values from MASW and microtremor data included rock (SB), very dense soil (SC), stiff soil (SD) and soft soil (SE), while the site class based on vs30 N-SPT data fell under the stiff soil (SD) criteria. The correlation between vs30 values obtained from MASW and microtremor measurements yielded a strong correlation coefficient (r) of 0.98, and the correlation between vs30 values from MASW and N-SPT measurements demonstrated a very strong correlation coefficient (r) of 0.99.

Plant Growth-Promotion and Abiotic Stress Tolerance of Dark Septate Endophyte Fungi Isolated from Roots of Native Andean Ericaceae Plants Colonizing Volcanic Deposits in Southern Chile

Plant Growth-Promotion and Abiotic Stress Tolerance of Dark Septate Endophyte Fungi Isolated from Roots of Native Andean Ericaceae Plants Colonizing Volcanic Deposits in Southern Chile

Origin of Groundwater in Kawung Carang Cold Spring, Sumbang District, Banyumas Regency, Central Java

Abstract The occurrence of several springs around Slamet Volcano raised questions regarding their origin. Many studies have been conducted to understand the origin of hot spring water around Slamet Volcano. Meanwhile, there has not been any research on the origin and hydrogeological system of cold spring water around Slamet Volcano. Kawung Carang Spring is one of cold spring water that occurs on the southern flank of Slamet Volcano. It is situated in a quaternary volcanic deposit of Mt. Slamet formation. Field observation was conducted to identify local geological conditions and hydrogeological systems in the research area. Isotopic analysis was performed to help understand how to delineate the recharge area. This study used a physical-chemical analysis of Kawung Carang cold spring water and the ratio of deuterium (2H) and 18O stable isotopes to interpret its groundwater origin. The results of the analysis informed that the origin of Kawung Carang spring water was local meteoric water. The hydrogeological system was an unconfined aquifer that consisted of a lahar deposit on the top of a volcanic breccia layer. The physical-chemical characteristic of groundwater around the Kawung Carang cold spring shows low electric conductivity (EC) and total dissolved solids (TDS) values. EC and TDS values of groundwater vary from 92 to 253 µS/cm and 46 to 126 mg/L indicating that groundwater has a short time in water-rock interaction process and comes from shallow depth aquifer. Furthermore, the signature of stable isotopes of δ18O and δ2H shows the elevation of the Kawung Carang cold spring recharge area ranges from 386.08 to 441.37 meters above sea level in the northwestern part of the research area.

Empirical Model of Unconsolidated Tephra Erosion: Verification and Application on Micro Catchment

Erosion is an important process that shapes the earth's surface. Given the complexity of the process, efforts to understand it are essential. Over the last 50 years, numerous models of soil particle erosion by surface runoff emerged, some of which share similar forms and parameters. The differences lie in the coefficient values of the parameters, attributed to the characteristics of the soil material such as texture, structure, and organic matter content. However, these erosion models tend to underpredict in the case of new volcanic deposit erosion. The erosion model for unconsolidated tephra, proposed by Yunita, was developed through laboratory experiments using volcanic material from Merapi Volcano, Indonesia. Nevertheless, the model has not been implemented for other cases. Therefore, this study aims to verify the erosion model for volcanic material in other cases, explore the possibility of broader implementation, identify the factors that influence its accuracy, and determine the model’s limitations. To verify the model’s potential for broader application, we applied it to micro-scale catchments in St. Hellens (USA), Sakurajima (Japan), and a laboratory scale plot in Merapi (Indonesia). The verification yielded satisfactory results for all three cases, especially for new tephra deposits. In the case of St. Helens, the extrapolation of model coefficients was proven to still be applicable even for thicker tephra layers. However, the erosion prediction was overestimated for tephra layer deposits older than 1 year, as the erosion rate decreases over time due to the compaction and stabilization of the tephra layer. In the Sakurajima, the model was also suitable for predicting long-term erosion amounts (daily and monthly). Meanwhile, in Merapi, the model provided accurate predictions for slopes of 20º and 25º but was less accurate for 30º slopes, where the measured erosion was due to both erosion and slope failure. These verification results demonstrate the potential of applying the empirical erosion model to micro catchments with relatively homogenous slopes and tephra properties. The sensitivity test revealed that slope, runoff, rainfall intensity, and volcanic ash thickness are strongly influence the erosion rate. This study also simplified the volcanic ash erosion model as a function of slope (S0), runoff (q), and rainfall (i) by assuming the value of (1-τc/τ0) is equal to 1. Further study using GIS tools is required for its application on several catchments with heterogeneous characteristics. Doi: 10.28991/CEJ-2024-010-07-02 Full Text: PDF

Recent faulting at the Claritas Rupes scarp on Mars

Endogenic processes have greatly affected the Martian surface, especially concentrating at several volcano-tectonic centers. The formation of Tharsis, a vast volcanic bulge, significantly influenced the western hemisphere of Mars. The associated loading stresses caused the formation of various sets of tectonic structures that might have remained active until today. However, surface evidence for very recent endogenic processes in Tharsis is sparse. Here, using the Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) images, we report the presence of fresh-appearing systems of local-scale scarps mostly developed at the southern edge of Tharsis, specifically at Claritas Rupes scarp. These scarps are spatially associated with depression centers situated at the base of Claritas Rupes, inside the Thaumasia Graben which is partially filled by volcanic deposits. The relationships between the studied scarps and present-day surficial processes and its deposits such as rockfalls indicate a young age of the scarps' development, namely, in the range of <1 Ma. The pristine topography (sharp and thin ridges), spatial distribution (association with depression centers), and regional geological context of Claritas Fossae lead us to interpret these scarps as surficial expressions of tectonic activity attributed to normal faulting. This could be related to Deep-seated Gravitational Slope Deformations (DGSDs) released by seismic activity related to ongoing subsidence of depression centers and/or reactivation of the listric normal Claritas Rupes fault. These observations imply that this region experienced long-lasting and multiple volcano-tectonic events and the formation of the youngest deformations could represent neotectonic activity, which has been active until recently, and possibly might be still ongoing.

Volcanic-controlled basin architecture variation and dynamic sediment filling in the South Lufeng Sag, South China Sea

Volcanic-controlled changes of basin architectures and sediments have given rise to diverse and rapidly evolving “dynamic geomorphology,” which poses challenges to successful petroleum development. Nonetheless, the accompanying volcanic deposits and landforms often produce rich and distinct seismic responses within conventional sedimentary layers, offering vital support in addressing this critical issue. Based on this, we compared the volcanic activity stages, evolution of geomorphology, and sediment dispersal processes to determine the process of basinal evolution by analyzing the episodes and distribution of volcanic-related deposits, sub-stages, seismic facies, and attributes of deposits of the South Lufeng Sag in the Pearl River Mouth Basin, South China Sea. The widespread development of strong amplitude attributes and chaotic reflection variance cube attribute spatial perspectives reveal the evolution of both intrusive and effusive facies in the lower Wenchang Formation across three stages of volcanic activity. The seismic amplitude difference of the andesite and andesitic tuff unveils the transition of the depositional pathway from north to south in the west depression with change of depocenters, lays the foundation for the dynamic geomorphic evolution of the “transitional basin” in the region. In the middle Huizhou-Lufeng uplift, the chaotic reflection with weak amplitude and obvious diapir structures revealed by andesite constrain the distribution of sedimentary space and the transformation of sedimentary pathways within the basin, and the evolution process of the “restricted basin” is summarised in terms of sedimentary filling processes. The seismic amplitude differences of basalt and andesitic tuff - related sediments in the east depression record the process of transformation from a single sedimentary channel to multi-pathway transport, which is summarised as the evolutionary model of the “diffusive basin”. This study offers a meticulous exploration into the evolutionary trajectory of dynamic geomorphology and sedimentary accumulation in a basin regulated by volcanic activity. The findings pave the way for the extensive application of this methodology in petroleum development across various geographic regions.

Analysis Of The Potential Of Volcanic Aquifers In Supporting The Development Of Groundwater Resources In Bogor District, West Java

This research is crucial for understanding the aquifer potential of volcanic deposits as a sustainable groundwater source, especially in regions experiencing rapid urbanization and agricultural expansion. It aims to analyze the aquifer potential of volcanic deposits in Bogor Regency, focusing on the Bogor Groundwater Basin, the upper Cisadane watershed, the eastern slopes of Mount Salak, and the western slopes of Mount Pangrango. The methods used include secondary data collection from regional geological maps and primary data collection through field surveys, geological mapping, and hydrogeological mapping. The results show that the volcanic rock units in this area, consisting of stony tuff, tuff breccia, lava, and andesite lava, have unique characteristics with significant potential as aquifers. Detailed geomorphological and hydrogeological mapping revealed different types of springs and physical properties of water that support the sustainability of groundwater resources. These findings contribute significantly to the development of better groundwater management policies, effective water infrastructure development, and environmental conservation strategies in Bogor District, ensuring clean water availability for the future.

Analyzing possible seismic velocity changes in Mexico City using seismic noise interferometry

The seismic response of the Mexico City basin has received plenty of attention as one of the most relevant cases of ground motion amplification. A recent study showed possible velocity variations of the deposits in both the lake bed and firm ground. A clear drop in seismic velocity was observed during the 2017.09.19 earthquake (Mw 7.1) in addition to more subtle seismic velocity changes related to seasonal temperature and precipitation. We use continuous seismic noise data recorded in a 29 broadband seismograph network in and around Mexico City to investigate Rayleigh wave group velocity structure and velocity changes. We estimate Green's functions (GF) between station pairs using seismic noise cross-correlation. An average estimate is computed for each of three five-day periods of recording. GFs are dominated by a Rayleigh pulse at low frequencies (between 0.1 and 0.2 Hz). Velocity changes are investigated through the comparison between GF's for different five-day periods. No velocity variations are observed. Station pairs separated at a distance smaller than 20 km also show some Rayleigh wave energy at higher frequencies, between 0.3 and 1.2 Hz. We repeated the analysis in a higher frequency band (up to 5 Hz) and show that again no velocity variation can be observed. In addition, we used horizontal-to-vertical spectral ratios computed for both earthquake and seismic noise records to identify possible non-linear effects during the 2017 earthquake. The results showed that significant non-linear effects during that event are to be discarded. Finally, we present preliminary results of a tomography of Rayleigh wave group velocity at the center of the array. Lateral structure variations below the geotechnical zonation are significant. Our data will be useful to constrain the structure of the volcanic deposits of the Transmexican Volcanic Belt (TVB).