Preprints
Search for science and technology (46 results)
Large-Scale Controlled Experiment Demonstrates Effectiveness of Methane Leak Detection and Repair Programs at Oil and Gas Facilities
Published: 2021-12-09
Subjects: Earth Sciences, Environmental Sciences
The importance of reducing methane emissions from oil and gas operations as a near-term climate action is widely recognized. Most jurisdictions around the globe using leak detection and repair (LDAR) programs to find and fix methane leaks. In this work, we empirically evaluate the efficacy of LDAR programs using a large-scale, bottom-up, randomized controlled field experiment across ~200 oil and [...]
Unusual Suspects: “Allies in the Park, Are Closer Than They Appear”
Published: 2021-12-06
Subjects: Life Sciences, Social and Behavioral Sciences
One season, 1039 hours, as a Park Ranger at Mesa Verde National Park. Interps we are called, observing, telling stories, being stewards of the past, present and future of wildness. Wildness in the animal world is reserved to only 4% of the planets millions of animals, Wildness is why people come to the National Parks, they are the last stronghold of beauty that bears presence in each of our [...]
Variety of the drift pumice clasts from the 2021 Fukutoku-Oka-no-Ba eruption, Japan.
Published: 2021-11-25
Subjects: Geology, Volcanology
Pumice rafts that arrived at the Nansei Islands, Japan, provided a unique opportunity to investigate the Fukutoku-Oka-no-Ba (FOB) eruption of August 2021. Despite drifting for 2 months for ~1300 km, the drift pumice raft had a large volume and contained a variety of pumice clasts, some of which were deposited during a high tide in a typhoon, while others were washed up on a sandy beach. Most of [...]
Stalagmite evidence for Early Holocene multidecadal hydroclimate variability in Ethiopia
Published: 2021-09-22
Subjects: Geochemistry, Geology, Speleology
A multiproxy oxygen and carbon isotope (d13C and d18O), growth rate and trace element stalagmite paleoenvironmental record is presented for the Early Holocene from Achere Cave, Ethiopia. The annually laminated stalagmite grew from 10.6 to 10.4 ka, and from 9.7 to 9.0 ka with a short hiatus at ~9.25 ka. Using oxygen and carbon isotopic, and cave monitoring data, we demonstrate that the stalagmite [...]
ANALYSIS OF OWNER DRIVEN APPROACH OF HOUSING RECONSTRUCTION AFTER GORKHA EARTHQUAKE 2015: A CASE STUDY OF DHUNIBESHI MUNICIPALITY, DHADING
Published: 2021-05-26
Subjects: Engineering
A 7.6 magnitude earthquake occurred in Gorkha district of Nepal leading more than 9,000 estimated casualties, approximately 23,000 injuries and damages on more than half a million structures. For leading and managing the earthquake recovery and reconstruction in Nepal, a legally mandated agency named National Reconstruction Authority (NRA) was established in December 2015 which facilitate and [...]
Distributed Acoustic Sensing for Near Surface Imaging from Submarine Telecommunication Cable: Case Study in the Trondheim Fjord
Published: 2021-05-13
Subjects: Geophysics and Seismology, Geotechnical Engineering, Signal Processing, Systems and Communications
Distributed acoustic sensing (DAS) transforms submarine telecommunication cables into densely sampled seismic receivers. To demonstrate DAS applications for seismic imaging, we use an optical cable on the seafloor in the Trondheim Fjord, Norway, to record seismic data generated by a controlled seismic source. The data are simultaneously recorded by a towed hydrophone array and the fiber optic [...]
New Technologies can Cost-effectively Reduce Oil and Gas Methane Emissions, but Policies will Require Careful Design to Establish Mitigation Equivalence
Published: 2021-01-22
Subjects: Oil, Gas, and Energy
Reducing methane emissions from oil and gas systems is a central component of US and international climate policy. Leak detection and repair (LDAR) programs using optical gas imaging (OGI) based surveys are routinely used to mitigate fugitive emissions or leaks. Recently, new technologies and platforms such as planes, drones, and satellites promise more cost-effective methane mitigation than [...]
Global Liquefied Natural Gas Expansion Exceeds Demand for Coal-to-gas Switching in Paris Compliant Pathways
Published: 2020-12-04
Subjects: Oil, Gas, and Energy, Sustainability
The shift from coal to natural gas (NG) in the power sector has led to significant reductions in carbon emissions. The shale gas revolution that led to this shift is now fueling a global expansion in liquefied natural gas (LNG) export infrastructure. In this work, we assess the viability of LNG expansion to reduce global carbon emissions through coal-to-gas switching in the power sector under [...]
A Machine Learning Approach to Methane Emissions Mitigation in the Oil and Gas Industry
Published: 2020-11-05
Subjects: Environmental Engineering, Systems Engineering
Reducing methane emissions from the oil and gas sector is a key component of climate policy in the United States. Methane leaks across the supply chain are stochastic and intermittent, with a small number of sites (‘super-emitters’) responsible for a majority of emissions. Thus, cost-effective emissions reduction critically relies on effectively identifying the super-emitters from thousands [...]
Characterizing seismic scattering in 3D heterogeneous Earth by a single parameter
Published: 2020-10-24
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We derive a theoretical parameter for three seismic scattering regimes where seismic wavelengths are either much shorter, similar, or much longer than the correlation length of small-scale Earth heterogeneities. We focus our analysis on the power spectral density of the von Karman autocorrelation function, used to characterize the spatial heterogeneity of small-scale variations of elastic rock [...]
Seismic energy radiation and along-strike heterogeneities of shallow tectonic tremors at the Nankai Trough and Japan Trench
Published: 2020-10-21
Subjects: Geophysics and Seismology
Shallow slow earthquakes have been documented along shallow plate interfaces near trenches. Recent geophysical observation networks located offshore of Japan enable us to analyze shallow tremors in the Nankai Trough and the Japan Trench. Onshore seismic stations are also important for detecting shallow very low frequency earthquakes (VLFEs) and for evaluating their seismicity prior to the [...]
The Volcanic & Magmatic Studies Group Equality, Diversity and Inclusion Report 2020
Published: 2020-07-24
Subjects: Earth Sciences, Education, Physical Sciences and Mathematics, Volcanology
The Volcanic and Magmatic Studies Group (VMSG) takes equality, diversity and inclusion (EDI) seriously and we recognise that the under-representation and/or unconscious marginalisation of any group impacts on our ability to fulfill our mission to serve the volcanology, petrology and geochemistry community. The following report summarises the findings from both the 2016-2020 VMSG annual meetings [...]
Dynamic fault interaction during a fluid-injection induced earthquake: The 2017 Mw 5.5 Pohang event
Published: 2020-03-03
Subjects: Earth Sciences, Geophysics and Seismology, Life Sciences, Physical Sciences and Mathematics
The November 15th, 2017 Mw 5.5 Pohang earthquake (South Korea) has been linked to hydraulic stimulation and fluid injections, making this the largest induced seismic event associated with an Enhanced Geothermal System (EGS). To understand its source dynamics and fault interactions, we conduct the first 3D high-resolution spontaneous dynamic rupture simulations of an induced earthquake. We account [...]
Effects of groundwater pumping on ground surface temperature: A regional modeling study in the North China Plain
Published: 2019-11-22
Subjects: Earth Sciences, Hydrology, Physical Sciences and Mathematics
Over-exploitation of groundwater (GW) in the North China Plain (NCP) since the 1960s has many environmental consequences. However, understanding of the dominant mechanisms remains limited, particularly at the regional scale. In this study, the coupled ParFlow.CLM model representing subsurface and land-surface processes and their interactions was applied in the NCP at high spatio-temporal [...]
Snow Depth and Snow Water Equivalent Estimation in the Northwestern Himalayan Watershed using Spaceborne Polarimetric SAR Interferometry
Published: 2019-06-27
Subjects: Earth Sciences, Engineering, Environmental Sciences, Hydrology, Physical Sciences and Mathematics, Water Resource Management
Snow depth (SD) and Snow Water Equivalent (SWE) constitute essential physical properties of snow and find extensive usage in the hydrological modelling domain. However, the prominent impact of the hydrometeorological conditions and difficult terrain conditions inhibit accurate measurement of the SD and SWE— an ongoing research problem in the cryosphere paradigm. In this context, spaceborne [...]