Publications
Google Scholar | ORCID: 0000-0002-3766-0876
2025
- Minute-scale dynamics of repeated dike intrusions in Iceland with fiber-optic geodesyJiaxuan Li, Ettore Biondi, Heimisson Elias, and 11 more authorsIn review, 2025
Continuous geodetic measurements near volcanic systems have revealed dynamic magmatic transport, yet capturing high spatio-temporal resolution dike intrusion dynamics remains challenging. We use low-frequency distributed acoustic sensing (LFDAS) recordings along a telecommunication fiber cable to track dike intrusions near Grindavík, Iceland. LFDAS recordings show distinct strain responses from nine intrusive events, six resulting in fissure eruptions. We image complex magma intrusions propagating on the minute time scale, forming observed lava fissures in eruptive events or remaining trapped at depth in arrested intrusions. Our results highlight the feasibility of using DAS for a dense array of strainmeters, enabling high-resolution, nearly real-time imaging of subsurface quasi-static deformations. In active volcanic regions, LFDAS recordings can offer critical insights into magmatic evolution, eruption forecasting, and volcanic hazard assessment.
2024
- Monitoring spatiotemporal evolution of fractures during hydraulic stimulations at the first EGS collab testbed using anisotropic elastic-waveform inversionZongcai Feng, Lianjie Huang, Benxin Chi, and 5 more authorsGeothermics, Sep 2024
The EGS Collab project acquired continuous active-source seismic monitoring (CASSM) data before, during, and after hydraulic stimulations at the first testbed at the depth of 4850 ft (1478 m) at the Sanford Underground Research Facility in Lead, South Dakota, for monitoring fracture creation and evolution. CASSM acquisition was conducted using 24 hydrophones, 18 accelerometers, and 17 piezoelectric sources within four fracture-parallel wells and two orthogonal wells. 3D anisotropic traveltime tomography and anisotropic elastic-waveform inversion of the campaign cross-borehole seismic data show that the rock within the stimulation region is a heterogeneous horizontal transverse isotropic medium. We use these inversion results as the initial models and apply 3D anisotropic first-arrival traveltime tomography and 3D anisotropic elastic-waveform inversion to the CASSM data acquired after each stimulation in May, 2018 and December, 2018. We observe the spatiotemporal evolution of seismic velocities and anisotropic parameters caused by hydraulic fracture stimulations, showing the regions of rock alternation caused by hydraulic fracture stimulation.
@article{feng_monitoring_2024, title = {Monitoring spatiotemporal evolution of fractures during hydraulic stimulations at the first {EGS} collab testbed using anisotropic elastic-waveform inversion}, volume = {122}, issn = {0375-6505}, url = {https://www.sciencedirect.com/science/article/pii/S0375650524001652}, doi = {10.1016/j.geothermics.2024.103076}, urldate = {2024-09-03}, journal = {Geothermics}, author = {Feng, Zongcai and Huang, Lianjie and Chi, Benxin and Gao, Kai and Li, Jiaxuan and Ajo-Franklin, Jonathan and Blankenship, Douglas A. and Kneafsey, Timothy J.}, month = sep, year = {2024}, keywords = {Anisotropic elastic-waveform inversion, Continuous Active-Source Seismic Monitoring (CASSM), EGS Collab, Enhanced geothermal systems, Hydraulic stimulation, Spatiotemporal evolution of fractures}, pages = {103076} } - Source mechanism of kHz microseismic events recorded in multiple boreholes at the first EGS Collab testbedYan Qin, Jiaxuan Li, Lianjie Huang, and 4 more authorsGeothermics, Jun 2024
Continuous microseismic monitoring using three-component (3C) accelerometers deployed in multiple boreholes allows for tracking the detailed evaluation of mesoscale (∼10 m scale) fracture growth during the fracture stimulation experiments at the first Enhanced Geothermal Systems (EGS) Collab testbed. Building on a well-constrained microseismic event catalog, we invert for moment tensor of the events to better understand the fracture geometry and stress orientations. However, it is challenging because of the unknown orientation of 3C accelerometers and low signal-to-noise-ratio nature of high-frequency (several kHz) monitoring. To address these challenges, we first perform the hodogram analysis on the continuous active-source seismic monitoring (CASSM) data to determine the orientations of the 18 3C accelerometers. We then apply the principal component analysis (PCA) to the observed microseismic waveforms to improve the signal-to-noise ratios. We perform a grid search for the full moment tensor by fitting the PCA-denoised waveforms at a frequency range of 5 to 8 kHz. The moment tensor results show both the creation of hydraulic fractures and the reactivation of natural fractures during the hydraulic stimulations. Our stress inversion based on the inverted moment tensors reveals the alteration of stress regime caused by hydraulic fracture stimulations.
@article{qin_source_2024, title = {Source mechanism of {kHz} microseismic events recorded in multiple boreholes at the first {EGS} {Collab} testbed}, volume = {120}, copyright = {All rights reserved}, issn = {0375-6505}, url = {https://www.sciencedirect.com/science/article/pii/S037565052400083X}, doi = {10.1016/j.geothermics.2024.102994}, urldate = {2024-03-20}, journal = {Geothermics}, author = {Qin, Yan and Li, Jiaxuan and Huang, Lianjie and Schoenball, Martin and Ajo-Franklin, Jonathan and Blankenship, Douglas and Kneafsey, Timothy J.}, month = jun, year = {2024}, keywords = {EGS Collab, High frequency (kHz), Hydraulic fracturing, Microseismic monitoring, Moment tensor, Multiple boreholes, Stress state}, pages = {102994} } - Detection of Earthquake Infragravity and Tsunami Waves With Underwater Distributed Acoustic SensingHan Xiao, Zack J. Spica, Jiaxuan Li, and 1 more authorGeophysical Research Letters, Jun 2024
Underwater Distributed Acoustic Sensing (DAS) utilizes optical fiber as a continuous sensor array. It enables high-resolution data collection over long distances and holds promise to enhance tsunami early warning capabilities. This research focuses on detecting infragravity and tsunami waves associated with earthquakes and understanding their origin and dispersion characteristics through frequency-wavenumber domain transformations and beamforming techniques. We propose a velocity correction method based on adjusting the apparent channel spacing according to water depth to overcome the challenge of detecting long-wavelength and long-period tsunami signals. Experimental results demonstrate the successful retrieval of infragravity and tsunami waves using a subsea optical fiber in offshore Oregon. These findings underscore the potential of DAS technology to complement existing infragravity waves detection systems, enhance preparedness, and improve response efforts in coastal communities. Further research and development in this field are crucial to fully utilize the capabilities of DAS for enhanced tsunami monitoring and warning systems.
@article{xiao_detection_2024, title = {Detection of {Earthquake} {Infragravity} and {Tsunami} {Waves} {With} {Underwater} {Distributed} {Acoustic} {Sensing}}, volume = {51}, copyright = {© 2024. The Authors.}, issn = {1944-8007}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023GL106767}, doi = {10.1029/2023GL106767}, language = {en}, number = {2}, urldate = {2024-01-27}, journal = {Geophysical Research Letters}, author = {Xiao, Han and Spica, Zack J. and Li, Jiaxuan and Zhan, Zhongwen}, year = {2024}, pages = {e2023GL106767} }
2023
- Seismic arrival-time picking on distributed acoustic sensing data using semi-supervised learningWeiqiang Zhu, Ettore Biondi, Jiaxuan Li, and 3 more authorsNatureComms, Dec 2023
Distributed Acoustic Sensing (DAS) is an emerging technology for earthquake monitoring and subsurface imaging. However, its distinct characteristics, such as unknown ground coupling and high noise level, pose challenges to signal processing. Existing machine learning models optimized for conventional seismic data struggle with DAS data due to its ultra-dense spatial sampling and limited manual labels. We introduce a semi-supervised learning approach to address the phase-picking task of DAS data. We use the pre-trained PhaseNet model to generate noisy labels of P/S arrivals in DAS data and apply the Gaussian mixture model phase association (GaMMA) method to refine these noisy labels and build training datasets. We develop PhaseNet-DAS, a deep learning model designed to process 2D spatio-temporal DAS data to achieve accurate phase picking and efficient earthquake detection. Our study demonstrates a method to develop deep learning models for DAS data, unlocking the potential of integrating DAS in enhancing earthquake monitoring.
@article{zhu_seismic_2023, title = {Seismic arrival-time picking on distributed acoustic sensing data using semi-supervised learning}, volume = {14}, copyright = {2023 The Author(s)}, issn = {2041-1723}, url = {https://www.nature.com/articles/s41467-023-43355-3}, doi = {10.1038/s41467-023-43355-3}, language = {en}, number = {1}, urldate = {2023-12-17}, journal = {NatureComms}, author = {Zhu, Weiqiang and Biondi, Ettore and Li, Jiaxuan and Yin, Jiuxun and Ross, Zachary E. and Zhan, Zhongwen}, month = dec, year = {2023}, keywords = {Geophysics, Seismology}, pages = {8192} } - An upper-crust lid over the Long Valley magma chamberEttore Biondi, Weiqiang Zhu, Jiaxuan Li, and 2 more authorsScience Advances, Oct 2023
Geophysical characterization of calderas is fundamental in assessing their potential for future catastrophic volcanic eruptions. The mechanism behind the unrest of Long Valley Caldera in California remains highly debated, with recent periods of uplift and seismicity driven either by the release of aqueous fluids from the magma chamber or by the intrusion of magma into the upper crust. We use distributed acoustic sensing data recorded along a 100-kilometer fiber-optic cable traversing the caldera to image its subsurface structure. Our images highlight a definite separation between the shallow hydrothermal system and the large magma chamber located at ~12-kilometer depth. The combination of the geological evidence with our results shows how fluids exsolved through second boiling provide the source of the observed uplift and seismicity.
@article{biondi_upper-crust_2023, title = {An upper-crust lid over the {Long} {Valley} magma chamber}, volume = {9}, copyright = {All rights reserved}, url = {https://www.science.org/doi/full/10.1126/sciadv.adi9878}, doi = {10.1126/sciadv.adi9878}, number = {42}, urldate = {2023-10-18}, journal = {Science Advances}, author = {Biondi, Ettore and Zhu, Weiqiang and Li, Jiaxuan and Williams, Ethan F. and Zhan, Zhongwen}, month = oct, year = {2023}, pages = {eadi9878} } - The break of earthquake asperities imaged by distributed acoustic sensingJiaxuan Li, Taeho Kim, Nadia Lapusta, and 2 more authorsNature. Research briefing , Aug 2023
Rupture imaging of megathrust earthquakes with global seismic arrays revealed frequency-dependent rupture signatures1–4, but the role of high-frequency radiators remains unclear3–5. Similar observations of the more abundant crustal earthquakes could provide critical constraints but are rare without ultradense local arrays6,7. Here we use distributed acoustic sensing technology8,9 to image the high-frequency earthquake rupture radiators. By converting a 100-kilometre dark-fibre cable into a 10,000-channel seismic array, we image four high-frequency subevents for the 2021 Antelope Valley, California, moment-magnitude 6.0 earthquake. After comparing our results with long-period moment-release10,11 and dynamic rupture simulations, we suggest that the imaged subevents are due to the breaking of fault asperities—stronger spots or pins on the fault—that substantially modulate the overall rupture behaviour. An otherwise fading rupture propagation could be promoted by the breaking of fault asperities in a cascading sequence. This study highlights how we can use the extensive pre-existing fibre networks12 as high-frequency seismic antennas to systematically investigate the rupture process of regional moderate-sized earthquakes. Coupled with dynamic rupture modelling, it could improve our understanding of earthquake rupture dynamics.
@article{li_break_2023, title = {The break of earthquake asperities imaged by distributed acoustic sensing}, copyright = {2023 The Author(s), under exclusive licence to Springer Nature Limited}, issn = {1476-4687}, url = {https://www.nature.com/articles/s41586-023-06227-w}, doi = {10.1038/s41586-023-06227-w}, language = {en}, urldate = {2023-08-02}, journal = {Nature}, author = {Li, Jiaxuan and Kim, Taeho and Lapusta, Nadia and Biondi, Ettore and Zhan, Zhongwen}, month = aug, year = {2023}, keywords = {Fibre optics and optical communications, Geophysics, Seismology}, pages = {1--7}, } - Earthquake focal mechanisms with distributed acoustic sensingJiaxuan Li, Weiqiang Zhu, Ettore Biondi, and 1 more authorNature Communications, Jul 2023
Earthquake focal mechanisms provide critical in-situ insights about the subsurface faulting geometry and stress state. For frequent small earthquakes (magnitude\textless 3.5), their focal mechanisms are routinely determined using first-arrival polarities picked on the vertical component of seismometers. Nevertheless, their quality is usually limited by the azimuthal coverage of the local seismic network. The emerging distributed acoustic sensing (DAS) technology, which can convert pre-existing telecommunication cables into arrays of strain/strain-rate meters, can potentially fill the azimuthal gap and enhance constraints on the nodal plane orientation through its long sensing range and dense spatial sampling. However, determining first-arrival polarities on DAS is challenging due to its single-component sensing and low signal-to-noise ratio for direct body waves. Here, we present a data-driven method that measures P-wave polarities on a DAS array based on cross-correlations between earthquake pairs. We validate the inferred polarities using the regional network catalog on two DAS arrays, deployed in California and each comprising ~ 5000 channels. We demonstrate that a joint focal mechanism inversion combining conventional and DAS polarity picks improves the accuracy and reduces the uncertainty in the focal plane orientation. Our results highlight the significant potential of integrating DAS with conventional networks for investigating high-resolution earthquake source mechanisms.
@article{li_earthquake_2023, title = {Earthquake focal mechanisms with distributed acoustic sensing}, volume = {14}, copyright = {2023 The Author(s)}, issn = {2041-1723}, url = {https://www.nature.com/articles/s41467-023-39639-3}, doi = {10.1038/s41467-023-39639-3}, language = {en}, number = {1}, urldate = {2023-07-16}, journal = {Nature Communications}, author = {Li, Jiaxuan and Zhu, Weiqiang and Biondi, Ettore and Zhan, Zhongwen}, month = jul, year = {2023}, keywords = {Fibre optics and optical communications, Seismology}, pages = {4181}, } - Earthquake Magnitude With DAS: A Transferable Data-Based Scaling RelationJiuxun Yin, Weiqiang Zhu, Jiaxuan Li, and 9 more authorsGeophysical Research Letters, Jul 2023
Distributed Acoustic Sensing (DAS) is a promising technique to improve the rapid detection and characterization of earthquakes. Previous DAS studies mainly focus on the phase information but less on the amplitude information. In this study, we compile earthquake data from two DAS arrays in California, USA, and one submarine array in Sanriku, Japan. We develop a data-driven method to obtain the first scaling relation between DAS amplitude and earthquake magnitude. Our results reveal that the earthquake amplitudes recorded by DAS in different regions follow a similar scaling relation. The scaling relation can provide a rapid earthquake magnitude estimation and effectively avoid uncertainties caused by the conversion to ground motions. Our results show that the scaling relation appears transferable to new regions with calibrations. The scaling relation highlights the great potential of DAS in earthquake source characterization and early warning.
@article{yin_earthquake_2023, title = {Earthquake {Magnitude} {With} {DAS}: {A} {Transferable} {Data}-{Based} {Scaling} {Relation}}, volume = {50}, copyright = {All rights reserved}, issn = {1944-8007}, shorttitle = {Earthquake {Magnitude} {With} {DAS}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2023GL103045}, doi = {10.1029/2023GL103045}, language = {en}, number = {10}, urldate = {2023-05-23}, journal = {Geophysical Research Letters}, author = {Yin, Jiuxun and Zhu, Weiqiang and Li, Jiaxuan and Biondi, Ettore and Miao, Yaolin and Spica, Zack J. and Viens, Loïc and Shinohara, Masanao and Ide, Satoshi and Mochizuki, Kimihiro and Husker, Allen L. and Zhan, Zhongwen}, year = {2023}, keywords = {distributed acoustic sensing, earthquake magnitude scaling, source characterization}, pages = {e2023GL103045} } - Microseismic Monitoring at the Farnsworth CO2-EOR FieldYan Qin, Jiaxuan Li, Lianjie Huang, and 13 more authorsEnergies, Jan 2023
The Farnsworth Unit in northern Texas is a field site for studying geologic carbon storage during enhanced oil recovery (EOR) using CO2. Microseismic monitoring is essential for risk assessment by detecting fluid leakage and fractures. We analyzed borehole microseismic data acquired during CO2 injection and migration, including data denoising, event detection, event location, magnitude estimation, moment tensor inversion, and stress field inversion. We detected and located two shallow clusters, which occurred during increasing injection pressure. The two shallow clusters were also featured by large b values and tensile cracking moment tensors that are obtained based on a newly developed moment tensor inversion method using single-borehole data. The inverted stress fields at the two clusters showed large deviations from the regional stress field. The results provide evidence for microseismic responses to CO2/fluid injection and migration.
@article{qin_microseismic_2023, title = {Microseismic {Monitoring} at the {Farnsworth} {CO2}-{EOR} {Field}}, volume = {16}, copyright = {http://creativecommons.org/licenses/by/3.0/}, issn = {1996-1073}, url = {https://www.mdpi.com/1996-1073/16/10/4177}, doi = {10.3390/en16104177}, language = {en}, number = {10}, urldate = {2023-10-01}, journal = {Energies}, author = {Qin, Yan and Li, Jiaxuan and Huang, Lianjie and Gao, Kai and Li, David and Chen, Ting and Bratton, Tom and El-kaseeh, George and Ampomah, William and Ispirescu, Titus and Cather, Martha and Balch, Robert and Zheng, Yingcai and Tang, Shuhang and McCormack, Kevin L. and McPherson, Brian}, month = jan, year = {2023}, keywords = {CO$_{\textrm{2}}$-EOR, enhanced oil recovery, microseismic detection, microseismic monitoring, moment tensor inversion, stress field inversion}, pages = {4177} }
2022
- US PatentMethod of geochemical characterization, production allocation, and monitoring using trace and ultra-trace element analysisJohn F. Casey, Yongjun Gao, Weihang Yang, and 1 more authorOct 2022
2021
- ConferencePhysics-Guided Machine Learning Approach to Characterizing Small-Scale Fractures in Geothermal FieldsYingcai Zheng, Jiaxuan Li, Rongrong Lin, and 3 more authorsFeb 2021
Characterizing fracture zones is crucial in geothermal exploration, drilling, and development. We aim to characterize small-scale fractures with scales less than the seismic wavelength. Recently, machine learning (ML) methods have been popular in interpreting large-scale faults by finding offsets in seismic images. However, such offsets may not be associated with small-scale fractures. By shooting a seismic beam from the Earth’s surface to subsurface fracture zones, we can extract a receiver-beam interference pattern created by fracturegenerated multiple-scattering waves in observed seismic data. The double-beam interference pattern is a two-dimensional image that carries information about the discrete fracture network pattern. Under the ideal situation (e.g., perfect data acquisition and homogeneous medium), the beam inference pattern and the discrete fracture pattern are Fourier transform pairs. However, in real-world cases, such a Fourier transform relation is perturbed. We need to train the machine learning algorithm to be able to handle such a physical constraint. To demonstrate the capability of the method for small-scale fracture characterization, we construct a subsurface model containing smallscale fractures based on the Soda Lake geothermal field. We perform seismic modeling to generate 3D seismic data and apply our method to the data to characterize the discrete fractures, which are almost invisible on conventional seismic migration images.
2020
- A Numerical Study on the Effects of Heterogeneity, Anisotropy, and Station Coverage on the Compensated Linear Vector Dipole Component of Deep Earthquake Moment TensorsJiaxuan Li, Yingcai Zheng, and Xinding FangMay 2020arXiv:2005.12465
The moment tensors of a large portion of deep earthquakes show apparent non-double-couple (non-DC) components. Previously, the observed apparent non-DC values in deep earthquakes have been attributed to different mechanisms such as complex source processes or complicated source medium structures. In this paper, we focused on evaluating the second mechanism. We investigated the effect of slab heterogeneity, supra-slab anisotropic structure, intra-slab weakly anisotropic structure (e.g., the purported existence of the metastable olivine wedge), and non-uniform station coverage, on the non-DC radiation patterns of deep earthquakes using our 3-dimensional elastic finite-difference modeling and full-waveform inversion of moment tensors. We found that these investigated issues cannot cause the observed non-double-couple radiation patterns and the in-situ structure with strong S-wave anisotropy near to the earthquake focus is the simplest way to account for the apparent non-DC components in the radiation patterns of deep earthquakes.
2019
- ConferencePhysics-guided machine learning identification of discrete fractures from double beam imagesJiaxuan Li, Hao Hu, and Yingcai ZhengIn SEG Technical Program Expanded Abstracts 2019, Aug 2019
@incollection{li_physics-guided_2019, series = {{SEG} {Technical} {Program} {Expanded} {Abstracts}}, title = {Physics-guided machine learning identification of discrete fractures from double beam images}, url = {https://library.seg.org/doi/abs/10.1190/segam2019-3216786.1}, urldate = {2022-07-13}, booktitle = {{SEG} {Technical} {Program} {Expanded} {Abstracts} 2019}, publisher = {Society of Exploration Geophysicists}, author = {Li, Jiaxuan and Hu, Hao and Zheng, Yingcai}, month = aug, year = {2019}, doi = {10.1190/segam2019-3216786.1}, keywords = {machine learning, fracture imaging, neural networks}, pages = {2433--2437} } - 3D Staggered-grid finite-difference modeling of seismic waves in elastic media with discrete fracturesJiaxuan Li, Houzhu Zhang, and Abdulmohsen AlAliAug 2019
- Generation of a stochastic binary field that fits a given heterogeneity power spectrumJiaxuan Li, and Yingcai ZhengGeophysical Journal International, Jul 2019
Incomplete binary mixing of two components can form a heterogeneous assemblage in space. The heterogeneity power spectrum of the assemblage can be frequently obtained in observation. However, it is unknown if one can find a stochastic binary field to generate the observed spectrum. We propose a novel and powerful constructive procedure for this purpose. The procedure allows us not only to test whether certain binary mixing is feasible but also to tightly constrain the properties of the mixing components and the modal proportion. The method should find wide applications in many branches of geosciences.
@article{li_generation_2019, title = {Generation of a stochastic binary field that fits a given heterogeneity power spectrum}, volume = {217}, copyright = {All rights reserved}, issn = {0956-540X}, url = {https://doi.org/10.1093/gji/ggz024}, doi = {10.1093/gji/ggz024}, number = {1}, urldate = {2022-06-28}, journal = {Geophysical Journal International}, author = {Li, Jiaxuan and Zheng, Yingcai}, month = jul, year = {2019}, pages = {294--300} } - Preparing for InSight: Evaluation of the Blind Test for Martian SeismicityMartin Driel, Savas Ceylan, John Francis Clinton, and 67 more authorsSeismological Research Letters, Jun 2019
In December 2018, the National Aeronautics and Space Administration (NASA) Interior exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission deployed a seismometer on the surface of Mars. In preparation for the data analysis, in July 2017, the marsquake service initiated a blind test in which participants were asked to detect and characterize seismicity embedded in a one Earth year long synthetic data set of continuous waveforms. Synthetic data were computed for a single station, mimicking the streams that will be available from InSight as well as the expected tectonic and impact seismicity, and noise conditions on Mars (Clinton et al., 2017). In total, 84 teams from 20 countries registered for the blind test and 11 of them submitted their results in early 2018. The collection of documentations, methods, ideas, and codes submitted by the participants exceeds 100 pages. The teams proposed well established as well as novel methods to tackle the challenging target of building a global seismicity catalog using a single station. This article summarizes the performance of the teams and highlights the most successful contributions.
@article{van_driel_preparing_2019, title = {Preparing for {InSight}: {Evaluation} of the {Blind} {Test} for {Martian} {Seismicity}}, volume = {90}, copyright = {All rights reserved}, issn = {0895-0695}, shorttitle = {Preparing for {InSight}}, url = {https://doi.org/10.1785/0220180379}, doi = {10.1785/0220180379}, number = {4}, urldate = {2023-06-05}, journal = {Seismological Research Letters}, author = {van Driel, Martin and Ceylan, Savas and Clinton, John Francis and Giardini, Domenico and Alemany, Hector and Allam, Amir and Ambrois, David and Balestra, Julien and Banerdt, Bruce and Becker, Dirk and Böse, Maren and Boxberg, Marc S. and Brinkman, Nienke and Casademont, Titus and Chèze, Jérôme and Daubar, Ingrid and Deschamps, Anne and Dethof, Fabian and Ditz, Manuel and Drilleau, Melanie and Essing, David and Euchner, Fabian and Fernando, Benjamin and Garcia, Raphael and Garth, Thomas and Godwin, Harriet and Golombek, Matthew P. and Grunert, Katharina and Hadziioannou, Celine and Haindl, Claudia and Hammer, Conny and Hochfeld, Isabell and Hosseini, Kasra and Hu, Hao and Kedar, Sharon and Kenda, Balthasar and Khan, Amir and Kilchling, Tabea and Knapmeyer‐Endrun, Brigitte and Lamert, Andre and Li, Jiaxuan and Lognonné, Philippe and Mader, Sarah and Marten, Lorenz and Mehrkens, Franziska and Mercerat, Diego and Mimoun, David and Möller, Thomas and Murdoch, Naomi and Neumann, Paul and Neurath, Robert and Paffrath, Marcel and Panning, Mark P. and Peix, Fabrice and Perrin, Ludovic and Rolland, Lucie and Schimmel, Martin and Schröer, Christoph and Spiga, Aymeric and Stähler, Simon Christian and Steinmann, René and Stutzmann, Eleonore and Szenicer, Alexandre and Trumpik, Noah and Tsekhmistrenko, Maria and Twardzik, Cédric and Weber, Renee and Werdenbach‐Jarklowski, Philipp and Zhang, Shane and Zheng, Yingcai}, month = jun, year = {2019}, pages = {1518--1534} } - A new method of geochemical allocation and monitoring of commingled crude oil production using trace and ultra-trace multi-element analysesWeihang Yang, John F. Casey, Yongjun Gao, and 1 more authorFuel, Apr 2019
Production allocation refers to the practice of quantifying proportions of extracted commingled hydrocarbons across various contributing sources. In this paper we tested a new geochemical technique of trace element production allocation by analyzing the mass fractions of specific target elements in five end-member natural crude oils and the manually mixed crude oil in precisely controlled proportions. We analyzed target elements by ICP-OES and Triple Quadrupole (QQQ)-ICP-MS techniques in tandem on each sample. In our test, the contributing fractions of the five end-member oils were measured by weight and mixed in proportions of ∼30%, 25%, 20%, 15%, and 10% in the commingled oil. The obtained mass fractions for specific target elements in both the five end-member oils and the commingled oil are input into a program developed called “ALLO-TRACE”. ALLO-TRACE calculates the contributing fractions of all the end-member oils to the commingled oil using multiple analyte-based linear equations. Our repeated tests have shown that the calculated contribution fractions based on the mass fractions of multiple trace elements agree well with their known contribution fractions in the commingled oil. Accuracies of most calculations for all the five end-member oil target proportions are within 4%, and the best can be less than 0.6% for all end members (average 0.17% and median 0.1%). Most calculation uncertainties in terms of relative standard deviations of the five end-member oils are within 3%, and the best can be less than 2.3% for all end members (average 1.2% and median 0.9%).
@article{yang_new_2019, title = {A new method of geochemical allocation and monitoring of commingled crude oil production using trace and ultra-trace multi-element analyses}, volume = {241}, copyright = {All rights reserved}, issn = {0016-2361}, url = {https://www.sciencedirect.com/science/article/pii/S0016236118321057}, doi = {10.1016/j.fuel.2018.12.049}, urldate = {2024-03-24}, journal = {Fuel}, author = {Yang, Weihang and Casey, John F. and Gao, Yongjun and Li, Jiaxuan}, month = apr, year = {2019}, keywords = {Commingled crude oil, Contribution fraction, Geochemical production allocation, Production monitoring, Trace elements, Triple Quadrupole-ICP-MS}, pages = {347--359} }
2018
- Deep earthquakes in subducting slabs hosted in highly anisotropic rock fabricJiaxuan Li, Yingcai Zheng, Leon Thomsen, and 2 more authorsNature Geoscience. News & Views by Prof. Romanowicz , Sep 2018
Analysis of deep subduction-zone earthquakes, those at depths greater than 60 km, reveals the physical and chemical properties of a descending oceanic lithosphere at mantle depths. Over the past five decades, it has been observed that a large fraction of deep earthquakes has non-double-couple (non-DC) seismic radiation patterns. In contrast, shallow earthquakes tend to have DC radiation patterns due to mechanisms of shear faulting. These observations have been used to argue that deep earthquakes rupture differently from shallow earthquakes. Here we show that the observed global distribution of non-DC deep earthquakes could be caused by shear faulting mechanisms, but in a highly anisotropic laminated rock fabric that surrounds the deep earthquakes within subducted slabs. For intermediate-depth earthquakes (~60–300 km), we found a large shear-wave anisotropy of ~25%, possibly caused by laminated fabric or aligned melt pockets oriented parallel to the slab interface, which provides new supporting evidence for the metamorphic dehydration reactions in slabs. However, at deep-focus depths (\textgreater300 km), the putative metastable phase-change mechanism alone cannot explain the seismic anisotropy. Instead, our results and those from recent experiments suggest materials such as magnesite, or perhaps carbonatite melt, may play a role in generating deep-focus earthquakes.
@article{li_deep_2018, title = {Deep earthquakes in subducting slabs hosted in highly anisotropic rock fabric}, volume = {11}, copyright = {2018 The Author(s)}, issn = {1752-0908}, url = {https://www.nature.com/articles/s41561-018-0188-3}, doi = {10.1038/s41561-018-0188-3}, language = {en}, number = {9}, urldate = {2022-06-28}, journal = {Nature Geoscience}, author = {Li, Jiaxuan and Zheng, Yingcai and Thomsen, Leon and Lapen, Thomas J. and Fang, Xinding}, month = sep, year = {2018}, keywords = {Seismology, Solid Earth sciences}, pages = {696--700}, }