Meters In Depth Research Articles

Data‐driven predictions of summertime visits to lakes across 17 US states

AbstractUsing a dataset of more than 51,000 US lakes, we estimated the relationship between summertime lake visits, lake water clarity, landscape features, and other amenities, where visits were estimated with counts of geo‐located photographs. Given the size and complexity of our dataset, we used a combination of machine learning techniques, imputation techniques, and a Poisson count model to estimate these relationships. We found that every additional meter of average summertime Secchi depth was associated with at least 7% more summertime lake visits, all else equal. Second, we found that lake amenities, such as beaches, boat launches, and public toilets, were more powerful predictors of visits than water clarity. Third, we found that visits to a lake were strongly influenced by the lake's accessibility and its distance to nearby lakes and the amenities the nearby lakes offered. Our research highlights the need for (1) a better understanding of how representative social media data are of actual recreational behavior, (2) the development of best practices to account for nonrandom patterns in missing natural feature data, and (3) a better understanding of the potential endogeneity in the lake visit–water quality relationships.

IDENTIFICATION OF THE ANCIENT LAKES BASED ON GRAVITY METHODS IN BOROBUDUR TEMPLE

Indonesia is a country that's well known for its heritages. One of the heritages is Borobudur Temple. Several studies say that the Borobudur was enclosed by a lake. Therefore, this study aims to see the remains of an ancient lake below the surface with gravity method. The process stage begins with obtaining the CBA (Complete Bouger Anomaly) and continues by separating the anomaly with a Bandpass Filter, and followed with 3D inverse modeling and FHD (First Horizontal Derivative) analysis. According to the residual map, there are only minor anomalies in the west, south, and east, ranging in magnitude from -0.539 to (-0.209) mGal. This anomaly is consistent with the location of the ancient lake around Borobudur. In the meantime, the 3D modeling of the FHD study reveals a geologic structure surrounding the Borobudur with an anomaly ranging from 0.00289 to 0.00480 mGal. A deposit layer thought to be an ancient lake is visible between 50 and 525 meters in depth over the east and west sides of the Borobudur temple, and beneath it is visible between 250 and 525 meters. This depth map provides additional evidence that the ancient lake beneath the Borobudur is located between 250 and 525 meters.

A Numerical Simulation of Internal Wave Propagation on a Continental Slope and Its Influence on Sediment Transport

Significant current velocity near the sea bottom can be induced by internal waves, even for water a few hundred meters in depth. In this study, a nonhydrostatic ocean model was applied to simulate the generation and propagation of internal waves on the continental slope of the northern SCS. Based on the analyses of the vertical profiles of the currents, the propagation of internal waves along the continental slope can be categorized into six modes. The bed shear stress and the bedload transport were calculated to analyze the general characteristics of sediment transport along the continental slope of the northern SCS. Generally, there was no sediment transport on the sea bottom induced by the internal waves when the water depth was deeper than 650 m or shallower than 80 m. The downslope sediment transport dominated the slope at a water depth range of 200~650 m, while the upslope sediment transport dominated the slope at a water depth range of 80~200 m. The predicted directions of the bedload transport are coincident with the field observations of sand wave migration on the continental slope, which further confirms that the main cause of the generation and formation of sand waves on the continental slope of the northern SCS is the strong bottom current induced by the shoaling process of internal waves.

Investigation of groundwater flow direction using Geospatial technology: A case study in part of Port Harcourt, Rivers State, Nigeria

A geospatial technique was used in some parts of the Port Harcourt metropolis to establish the direction of groundwater movement. This method included the use of twelve carefully selected boreholes and a variety of cutting-edge tools, such as depth meters, handheld GPS, and measuring tape. The static water level in the boreholes and the ground surface elevation in relation to the average sea level of the region were two of the variables that were gathered. High-end software was used to analyze the data in order to create groundwater flow direction maps and 3D visualizations for displaying the whole research region based on the fluctuation in static water levels. This software included Microsoft Excel, ArcGIS 10.4, and ArcScene 10.4. Afterward, the main and minor flow directions were identified. The results showed that groundwater in the area moves from the north to the south, with group 4 having the largest hydraulic gradient and group 1 coming in second. On the other hand, groups 3 and 2 had the lowest hydraulic gradient. The main factors influencing groundwater flow were determined to be gravity and external pressure brought on by pumping. The research region's southern regions are more vulnerable to groundwater pollution, which may result from zones with higher hydraulic heads, according to the flow pattern in the aquifer system. As a result, it is advised that residential boreholes and municipal water wells be located on the study area's northern sides, whereas sanitary landfills and garbage sites should only be located in the southwest.

DELINEATION OF UNCERTAINTIES IN ANISOTROPIC SHALLOW SUBSURFACE BY INTEGRATED GEOPHYSICAL AND GEOMECHANICAL EXAMINATION

This study focused on geophysical and geomechanical analyses to arbitrate weak zones in Limestone of Gaj formation. Two boreholes were drilled and used to facilitate downhole seismic experiment down to 30 meters of depth. The downhole seismic method was supplied compressional waves velocities for inspection of shallow subsurface properties to evaluate local site condition. The primary data of P-waves velocities are varying from 566 m/s to 1225 m/s (BH-1) 570 m/s to 1320 m/s (BH-2). The information of elastic moduli were derived from primary waves data through empirical relationships. The core samples were collected and examined for geotechnical investigation in the laboratory. This study contributes to ensure the engineering strength of the ground and concluded that the ignorance of substrate conditions may lead to instability or construction failure.

A multi-approach inventory of the blue carbon stocks of Posidonia oceanica seagrass meadows: Large scale application in Calvi Bay (Corsica, NW Mediterranean)

In Mediterranean, Posidonia oceanica develops a belowground complex structure (‘matte’) able to store large amounts of carbon over thousands of years. The inventory of blue carbon stocks requires the coupling of mapping techniques and in situ sediment sampling to assess the size and the variability of these stocks. This study aims to quantify the organic (Corg) and inorganic (Cinorg) carbon stocks in the P. oceanica matte of the Calvi Bay (Corsica) using sub-bottom profiler imagery and biogeochemical analysis of sediment cores. The matte thicknesses map (average ± SD: 2.2 m ± 0.4 m) coupled with marine benthic habitat cartography allows to estimate matte volume at 12 473 352 m3. The cumulative stocks were assessed at 20.2–50.3 kg Corg m−2 and 26.6–58.7 kg Cinorg m−2 within the first meter of depth on matte (3632 ± 486 cal yr BP). The data contributed to estimate the overall carbon stocks at 389 994 t Corg and 615 558 t Cinorg, offering a new insight of the heterogeneity of blue carbon stocks in seagrass meadows. Variability of carbon storage capacity of matte influenced by substrate is discussed.

From ka to Ma: A multi-timescale record of accelerating Cenozoic tectonic uplift between the Qilian Shan and Qaidam Basin, northern Tibetan Plateau

Constraining tectonic uplift history within the Tibetan Plateau is critical to understanding its deformational response to continental collision. However, it is difficult to extrapolate orogen-scale uplift history from any single method alone. Here, we combined high-resolution deep and shallow seismic imaging (on the order of 103 to 102 meters in depth, respectively) with geologic paleoseismic trenching (on the order of several meters in depth) in the Qilian Shan−Qaidam Basin (QSQB) transition zone within the northern Tibetan Plateau, which provide a fault-to-basin, ka-to-Ma-scale record of mountain building. Tectonic uplift began in the early Cenozoic (>40 Ma), with slow uplift rates persisting until ca. 15.3 Ma. Tectonic tilting with limited thrust faulting along the QSQB transition zone was the predominant form of deformation during this period. Accelerated uplift since the middle Miocene is attributed to the activation of more thrust faults, and an increase in fault vertical slip rates by an order of magnitude, reaching ∼0.2−0.25 mm/a.

Comparison of shallow water soft coral (Octocorallia) diversity and distribution among three islands in Makassar Strait, Indonesia

Abstract. Putra AW, Priawandiputra W, Litaay M, Atmowidi T. 2022. Comparison of shallow water soft coral (Octocorallia) diversity and distribution among three islands in Makassar Strait, Indonesia. Biodiversitas 23: 5951-5961. There are only a few soft coral research in Indonesia. In the last ten years, there has been only seven published research. On the other hand, there are still many areas that are still unexplored, and every unexplored location has a chance to find a new species, thus we did this research. This study aims to conduct biodiversity research in the selected areas where soft corals biodiversity papers have never been published before. The distribution of soft coral in three small islands in Makassar strait and close to Sulawesi main island is reported in this paper. We hope that there is a correlation between the soft coral community in each researched island. The research was done by using a modified visual census method with 50 meters transect in the shallow water area (approx. 5 meters in depth). The data was collected by diving, sampling, and capturing images of each species found. Identification was made by comparing morphological characteristics using the book soft coral and Sea fans by Fabricius and Alderslade and newest papers about soft coral. In total, there are 41 species belonging to 14 genera and eight families found in this research. There is not much correlation between these three islands' soft coral communities. Every island had its key species based on the characteristics of the underwater habitats. The genera Acrossota and Dendronephtya only occur in Barrang Caddi Island, while, Cladiella, Clavularia and Xenia were only found in Gusung Toraja Island, and Anthellia and Heteroxenia were only found in Pannikiang Island. The genera Litophyton, Lobophytum, Sarcophyton, and Sinularia were found in all three researched islands. The south side of every island has the highest species abundance compared to the North, West, and Eastside.

Potassium silicate alteration in porphyry copper‑gold deposits: a case study at the giant maar-diatreme hosted Grasberg deposit, Indonesia

Potassium silicate alteration is a hallmark of the porphyry copper deposits that supply two thirds of the world's annual copper demand. These deposits formed in the cores of calc-alkaline to alkaline volcanic systems from the flux of magmatic gas that transported copper and other metals from source to the surface. The giant 3.2 Ma Grasberg CuAu deposit formed within a maar-diatreme complex following a resurgence in magmatism. The defined resources of this deposit occur from a few hundred metres depth to 1.7 km below the paleosurface which, uniquely in this deposit, is partially preserved as a section of maar tuffs.Potassium silicate alteration has commonly been interpreted as being the result of the addition of potassium to the porphyry copper host rocks via pervasive interaction with a large volume of a potassium-rich brine that is commonly presumed to be of magmatic origin. However, the data reported here show that alteration at the deposit scale is essentially isochemical with respect to the major rock-forming components and that only sulphur and the economic metals (Cu, Mo, Au, etc.) are added by flux of reactive magmatic gas containing SO2 and HCl from source intrusions at depth. Silicate solubilities are very low so that only a minor fraction of the total alkalis in the host rock are extracted by alteration reactions and then discharged at the paleo-surface. Reaction of the magmatic gas phase with plagioclase results in the coupled deposition of anhydrite (CaSO4) and disproportionation of SO2 to release H2S. The in-situ release of H2S immediately scavenges Cu and other chalcophile metals from the continuing magmatic gas flux to form the Cu-, Fe- and other sulphides that, in sufficient concentration, make up the economic reserve available to mining.The sequestration of Ca into anhydrite, along with deposition of silica into early quartz veins, increases the concentration of the other major components (K2O, Na2O, MgO, etc) in the remaining silicate assemblage within the porous host rock. The result is the development of intermingled potassium-enriched silicate and sulphur-rich (anhydrite-sulphide) sub-assemblages that constitute the mineralised phyllic or potassic alteration zones. These crystallise according to their pressure and depth into alteration assemblages dominated by potassic phyllosilicates, quartz and pyrite in the phyllic alteration zone, and alkali feldspar and phlogopitic-biotite plus minor andalusite and corundum in the central potassic zone. Dissolution and recrystallisation of primary magmatic biotite in the host rock releases K as well as Fe, the latter (along with amphibole and feldspar) providing iron for the formation of chalcopyrite, bornite and pyrite. The in-situ release of H2S through anhydrite formation, immediately scavenges Cu and other chalcophile metals from the continuing magmatic gas flux to form the CuFe sulphides that, in sufficient concentration, make up the economic reserve available to mining. Understanding of the alteration processes during porphyry copper formation also provides insights into gas-solid reactions processes inside active magmatic arc volcanoes but the magnitude of copper mineralisation is dependent on the original metal content of the source of the magmatic gas phase.

A globally relevant stock of soil nitrogen in the Yedoma permafrost domain

Nitrogen regulates multiple aspects of the permafrost climate feedback, including plant growth, organic matter decomposition, and the production of the potent greenhouse gas nitrous oxide. Despite its importance, current estimates of permafrost nitrogen are highly uncertain. Here, we compiled a dataset of >2000 samples to quantify nitrogen stocks in the Yedoma domain, a region with organic-rich permafrost that contains ~25% of all permafrost carbon. We estimate that the Yedoma domain contains 41.2 gigatons of nitrogen down to ~20 metre for the deepest unit, which increases the previous estimate for the entire permafrost zone by ~46%. Approximately 90% of this nitrogen (37 gigatons) is stored in permafrost and therefore currently immobile and frozen. Here, we show that of this amount, ¾ is stored >3 metre depth, but if partially mobilised by thaw, this large nitrogen pool could have continental-scale consequences for soil and aquatic biogeochemistry and global-scale consequences for the permafrost feedback.

Stratigraphic styles of the Upper Paleocene-Lower Eocene rocks along the escarpment of Jabal Waddan, NW Libya

Abstract
 Upper Paleocene-Lower Eocene carbonate rocks along the escarpment of Jabal Waddan of NW Libya are displaying two major sedimentary cycles based on stratigraphic and foraminiferal attributes. The first one is representing by a regressive-transgressive sequence and is attributed to the Shurfah Formation. It indicates that during the Thanetian (Upper Paleocene) the deposition of the lower part (the Bú Rá's Member) was in shallow water depths of the subtidal environment under low energy conditions and is represented primarily by Dasycladacean and Codiacean green algae. Their association up-levels with small shallow benthic foraminifera such as miliolids and nonionids, however, may indicate a broad nearshore environment of deposition. The decline of the green algae and the prevalence of small-sized (<1 cm) and thick operculinids witnesses in the middle and upper parts (i.e. the Qaltah and Ammúr members) are characteristic of an open-shelf setting down to a water depth of a few dozen meters and typify warmwater habitats. Evidence of further deepening is indicated up-section by the existence of common shallow shark-teeth in a water depth limited to the photic zone ((<120 m)
 The second sedimentary cycle is showing a transgressive-regressive sequence and is ascribed to the Bishimah Formation. It shows that during the Ypresian (Lower Eocene) the deposition of the lower, middle and upper parts (i.e. Khayir, Wadi Zakim and Rawaghah members) of the Bishimah Formation was in the shallow marine neritic environment. The association of alveolinids with common textulariids in the lower and middle members points to a shallow inner shelf with water depth up to 60 m whereas their association with miliolids, nonionids and elphidiids seen at the upper levels indicate innermost shelf or restricted platform conditions. Evidence of further shallowing, however, is indicated up-section (the Rawaghah Member) by the presence of cross-bedded dolomitic limestone and chert nodules which delineate an advanced episode of the second sedimentary cycle. The closing part for the second cycle, however, is attributed to the overlying Al Jir Formation, elsewhere from the study area, in which a thick sequence of evaporates and chalky dolomites is reported to include a rich Spirolina-miliolid assemblage with globular alveolinids similar to those recovered from the studied deposits. Consequently, we recommend considering the Al Jir Formation as the upper member of the Bishimah Formation as originally described in the local literature. The boundary between the Ammúr Member of Shurfah Formation and the overlying khayir Member of the Bishimah Formation, however, is erosional everywhere in the study area and sets the contact between the first and second sedimentary cycles. It has been considered here to represent the Upper Paleocene/Lower Eocene boundary. Based on planktonic foraminiferal evidence, described from the subsurface of the Sirt Basin, the lower part of the khayir Member has been considered in the current study to represent a Ypresian (Lower Eocene) rather than Thanetian (Upper Paleocene) in age as previously thought

Middle Miocene (Serravallian) rhodoliths and coralline algal debris in carbonate ramps (Betic Cordillera, S Spain)

Serravallian (middle Miocene) coralline algal assemblages at the southern margin of the Guadalquivir Basin (southern Spain) occur as rhodoliths preserved in situ or very close to their growth habitats (autochthonous–parautochthonous assemblages) and also as reworked remains (allochthonous assemblages). The former assemblages consist of spherical rhodoliths built up by encrusting to warty plants and also of large fragments of branches, whereas the latter are mostly unrecognizable small fragments occurring in channeled packstone–grainstone beds. In both cases, the most abundant components are members of the order Hapalidiales (Mesophyllum roveretoi, Mesophyllum sp., Lithothamnion ramosissimum, and less frequently Phymatolithon group calcareum and Lithothamnion group corallioides). Laminar growths of Lithoporella minus and branches of Spongites group fruticulosus and Sporolithon sp. occur very rarely. There are also anecdotal records of Subterraniphyllum thomasii, extending its upper stratigraphic range up to the Serravallian in the western Tethys. The autochthonous–parautochthonous coralline algal assemblages formed in a middle ramp, at several tens of meters of water depth, as suggested by the dominance of Hapalidiales. The allochthonous assemblages represent fragments of coralline algae derived from the middle ramp and redeposited in deeper settings, most likely the outer ramp, due to storm-generated currents.

Mechanical behavior of Malan loess under unconfined compression conditions

Loess landslides result in heavy casualties and economic losses. Among them, toppling is one of the predominant failure modes in Malan loess. Loess toppling failure normally arises from deep vertical cracks, which tend to develop in the shoulder areas of loess slopes and extend to a depth of several meters. Under natural conditions, loess’ static lateral pressure coefficient is low and the loess mass within a 2 m horizontal depth from the slope surface approximates an unconfined compression stress state. In this work, we sought to further examine this unconfined compression state using acoustic emission monitoring and in situ computed tomography scans to investigate the mechanical behavior of Malan loess. Results indicated that Malan loess failed under compression-induced tension in unconfined compression condition. It exhibited the brittle failure with an abrupt release of elastic energy. The failure plane was at large angles and occurred nearly along the loading axis. This result coincided well with the vertiloess structure, which is characterized by vertically aligned strong units and weak segments. The above failure mode supports the formation of vertical cracks in the loess strata and consequently the toppling and crack sliding slope failures, as well as the formation of loess walls and columns.

An Attempt to Study Foundation Anchoring Conditions in Sedimentary Estuaries Using Integrated Methods

The search for and knowledge of the best conditions for anchoring the foundations of certain structures such as bridges, tunnels and quays in sedimentary estuaries is a challenge, for both scientists in general and engineers in particular. Indeed, wharves are structures that receive a lot of stresses and therefore require anchoring to avoid tilting and to guarantee their stability during service. This work, based on the analysis of data from seismic refraction methods, mechanical soundings and laboratory tests, characterises the terrain of the Wouri estuary in Central Africa. The objective is to determine and present the subsurface layers encountered as well as their characteristics, in order to define the best conditions for anchoring the foundations to ensure the stability of the quays to be built there. The seismic refraction campaign shows that the study area is relatively heterogeneous over the first 25 m, with velocities measured in the range 1520–1750 m/s; modulated in two distinct ranges, between 1520–1580 m/s characteristic of mud and loose sediments (alternating layers of clay, sand, loose silt) and the range 1580–1750 m/s corresponding to the signature of sandy-silty or compact clays. The mechanical tests show sedimentary soils, with alternating layers of sandy clay and clayey sand over the 42 m drilled, loose over the first 30 m in the bank area and over the first 15 m in the canal or dredge area, with a limit pressure of less than 1 MPa. Similarly, the soil samples taken and tested in the laboratory show that the soils are clayey over the first 30 metres, plastic and liquid with respect to their water content, respectively, below and above the liquidity limits, confirming their loose character. The results of seismic refraction, mechanical soundings and laboratory tests show that, in estuarine areas characterised by alternating sandy clay and clayey sand, there are not always hard formations in the first 25 metres of depth but, from a depth of 30 m, the soils become moderately compact and begin to form an anchoring layer sufficient to guarantee the stability of the quays against earth pressure forces.

Geotechnical Measurements for the Investigation and Assessment of Arctic Coastal Erosion—A Review and Outlook

Geotechnical data are increasingly utilized to aid investigations of coastal erosion and the development of coastal morphological models; however, measurement techniques are still challenged by environmental conditions and accessibility in coastal areas, and particularly, by nearshore conditions. These challenges are exacerbated for Arctic coastal environments. This article reviews existing and emerging data collection methods in the context of geotechnical investigations of Arctic coastal erosion and nearshore change. Specifically, the use of cone penetration testing (CPT), which can provide key data for the mapping of soil and ice layers as well as for the assessment of slope and block failures, and the use of free-fall penetrometers (FFPs) for rapid mapping of seabed surface conditions, are discussed. Because of limitations in the spatial coverage and number of available in situ point measurements by penetrometers, data fusion with geophysical and remotely sensed data is considered. Offshore and nearshore, the combination of acoustic surveying with geotechnical testing can optimize large-scale seabed characterization, while onshore most recent developments in satellite-based and unmanned-aerial-vehicle-based data collection offer new opportunities to enhance spatial coverage and collect information on bathymetry and topography, amongst others. Emphasis is given to easily deployable and rugged techniques and strategies that can offer near-term opportunities to fill current gaps in data availability. This review suggests that data fusion of geotechnical in situ testing, using CPT to provide soil information at deeper depths and even in the presence of ice and using FFPs to offer rapid and large-coverage geotechnical testing of surface sediments (i.e., in the upper tens of centimeters to meters of sediment depth), combined with acoustic seabed surveying and emerging remote sensing tools, has the potential to provide essential data to improve the prediction of Arctic coastal erosion, particularly where climate-driven changes in soil conditions may bias the use of historic observations of erosion for future prediction.

Zemin Taşıma Gücü Haritalarının Oluşturulması: Altınşehir (Adıyaman) Örneği

Şehirlerin hızlı nüfus artışına uydu kentler, fabrikalar, üniversite kampüsleri ve alışveriş merkezleri gibi önemli mühendislik yapılarının hizmete girmesi önemli sebeplerdendir. Adıyaman ilinin gelişim sürekliliğine de 2006 yılında kurulan Adıyaman Üniversitesi önemli bir sebep olmuştur. Gelen yeni nüfusun konut ihtiyacı üniversite kampüsü civarı tarım arazilerinde, yapılaşmaya izin verilerek karşılanmıştır. Çalışma alanındaki en küçük ve en yüksek taşıma gücü değerleri sırasıyla 14,5 t / m2 ve 18,9 t / m2 dir. Taşıma gücü haritası NetCad programıyla sahanın 1/20000 ölçekli topoğrafik haritasına, derinliği 1,5-4 metre arasında değişen zemin taşıma gücü değerleri işlenerek çizilmiştir. Çizilen bu harita yardımıyla parsel bazında zemin araştırması yapılmayan bölgelerin de zemin taşıma gücü değerleri hesaplanabilir.

Rapid Radiolytic Degradation of Amino Acids in the Martian Shallow Subsurface: Implications for the Search for Extinct Life.

Amino acids are fundamental to life as we know them as the monomers of proteins and enzymes. They are also readily synthesized under a variety of plausible prebiotic conditions and are common in carbon-rich meteorites. Thus, they represent a reasonable class of organics to target in the search for prebiotic chemistry or chemical evidence of life on Mars. However, regardless of their origin, amino acids and other organic molecules present in near-surface regolith and rocks on Mars can be degraded by exposure to cosmic rays that can penetrate to a depth of a few meters. We exposed several pure amino acids in dry and hydrated silicate mixtures and in mixtures of silicates with perchlorate salts to gamma radiation at various temperatures and radiation doses representative of the martian near-subsurface. We found that irradiation of amino acids mixed with dry silica powder increased the rate of amino acid radiolysis, with the radiolysis constants of amino acids in silicate mixtures at least a factor of 10 larger compared with the radiolysis constants of amino acids alone. The addition of perchlorate salts to the silicate samples or hydration of silicate samples further accelerated the rate of amino acid destruction during irradiation and increased the radiolysis constants by a factor of ∼1.5. Our results suggest that even low-molecular-weight amino acids could degrade in just ∼20 million years in the top 10 cm of the martian surface regolith and rock, and even faster if the material contains elevated abundances of hydrated silicate minerals or perchlorates. We did not detect evidence of amino acid racemization after gamma radiation exposure of the samples, which indicates that the chirality of some surviving amino acids may still be preserved. Our experimental results suggest serious challenges for the search of ancient amino acids and other potential organic biosignatures in the top 2 m of the martian surface.

Social Responsibility According to Imam Al-Juwaini in his Book “Ghiyath al-Umam Fi Al-Thiath Al-Zulm”: A Fundamental Study

The study intends to identify both the geomorphologic and hydrological characteristics of Lake Sawa regarding its water sources and the specific attributes of this water. The study focused on the impact of climate on lake surface water's physical and chemical properties. The analysis of both the data for a major climate cycle (30 years) for the period (1989- 2018) and the samples taken from Lake Sawa water depth (1-5) meters proved that the climate had changed the physical and chemical properties of lake water; besides, the extensive evaporation of its water and the lack of rain precipitation in the lake raised salts ratio to 22885 (mg/liter), as well as the rates of other physical and chemical elements.

Underwater Excavation at the Basilica Church in İznik Lake – 2019

The remains of the basilical church lie approximately in 2 or 3 meters of depth, and 50 m from the shore of the lake, outside the city walls that surround the ancient city of Nicaea. The underwater archaeological excavations at the basilica remain are being launched under the auspices of the Iznik Archaeology Museum with the permission of the Ministry of Culture and Tourism in 2015. In 2019, excavation was carried out in the atrium where we thought a water well was situated. This is because the British pilgrim, Willibald, pointed out that the site of the 1st Council had a rectangular open-roofed courtyard with a sacred source of oil in the middle. Although we went down 60 cm deeper than the foundation walls, we could not find the bottom of the well. However, a large number of ceramics, glass bracelets, or Scyphate coins (cup-shaped coins) were found indicating the 13th century. It was also found that the well was filled with stone. Therefore, we think that the structure was definitely abandoned in the approximately 12th century and then sank into the lake waters.

Antarctic Firn Characterization via Wideband Microwave Radiometry

Recent studies have demonstrated that wideband microwave radiometers provide significant potential for profiling important subsurface polar firn characteristics necessary to understand the dynamics of the cryosphere and predict future changes in ice and snow coverage. Different frequencies within the wide spectra of radiometers result in different electromagnetic propagation losses and thus reveal characteristics at different depths in ice and snow. This paper, expanding on those investigations, explores the utilization of the Global Precipitation Measurement (GPM) constellation as a single wideband (6.93 GHz–91.655 GHz) spaceborne radiometer, covering the entire microwave spectrum from C-band to W-band, to profile subsurface properties of the Antarctic firn. Results of the initial analyses over Concordia and Vostok Stations in Antarctica indicate that GPM brightness temperature measurements provide critical information regarding the subsurface temperatures and physical properties of the firn from the surface down to several meters of depth. Considering the high spatiotemporal coverage of polar-orbiting spaceborne radiometers, these results are promising for future continent-level thermal and physical characterization of the Antarctic firn.