Ettore Biondi

All Publications

• Minute-scale dynamics of recurrent dike intrusions in Iceland with fiber-optic geodesy. Science (New York, N.Y.) Li, J., Biondi, E., Heimisson, E. R., Puel, S., Zhai, Q., Zhang, S., Hjörleifsdóttir, V., Wei, X., Bird, E., Klesh, A., Kamalov, V., Gunnarsson, T., Geirsson, H., Zhan, Z. 2025: eadu0225

  Abstract

  Continuous geodetic measurements near volcanic systems can image magma transport dynamics, yet resolving dike intrusions with high spatiotemporal resolution remains challenging. We introduce fiber-optic geodesy, leveraging low-frequency distributed acoustic sensing (LFDAS) recordings along a telecommunication fiber-optic cable, to track dike intrusions near Grindavík, Iceland, on a minute timescale. LFDAS reveals distinct strain responses from nine intrusive events, six resulting in fissure eruptions. Geodetic inversion of LFDAS strain reveals detailed magmatic intrusions, with inferred dike volume rate peaking systematically 15 to 22 min before the onset of each eruption. Our results demonstrate DAS's potential for a dense strainmeter array, 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 hazard assessment.

  View details for DOI 10.1126/science.adu0225

  View details for PubMedID 40273283

• Fiber-optic seismic sensing of vadose zone soil moisture dynamics. Nature communications Shen, Z., Yang, Y., Fu, X., Adams, K. H., Biondi, E., Zhan, Z. 2024; 15 (1): 6432

  Abstract

  Vadose zone soil moisture is often considered a pivotal intermediary water reservoir between surface and groundwater in semi-arid regions. Understanding its dynamics in response to changes in meteorologic forcing patterns is essential to enhance the climate resiliency of our ecological and agricultural system. However, the inability to observe high-resolution vadose zone soil moisture dynamics over large spatiotemporal scales hinders quantitative characterization. Here, utilizing pre-existing fiber-optic cables as seismic sensors, we demonstrate a fiber-optic seismic sensing principle to robustly capture vadose zone soil moisture dynamics. Our observations in Ridgecrest, California reveal sub-seasonal precipitation replenishments and a prolonged drought in the vadose zone, consistent with a zero-dimensional hydrological model. Our results suggest a significant water loss of 0.25 m/year through evapotranspiration at our field side, validated by nearby eddy-covariance based measurements. Yet, detailed discrepancies between our observations and modeling highlight the necessity for complementary in-situ validations. Given the escalated regional drought risk under climate change, our findings underscore the promise of fiber-optic seismic sensing to facilitate water resource management in semi-arid regions.

  View details for DOI 10.1038/s41467-024-50690-6

  View details for PubMedID 39103375

  View details for PubMedCentralID PMC11300608

• Seismic arrival-time picking on distributed acoustic sensing data using semi-supervised learning. Nature communications Zhu, W., Biondi, E., Li, J., Yin, J., Ross, Z. E., Zhan, Z. 2023; 14 (1): 8192

  Abstract

  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.

  View details for DOI 10.1038/s41467-023-43355-3

  View details for PubMedID 38081845

  View details for PubMedCentralID PMC10713581

• An upper-crust lid over the Long Valley magma chamber. Science advances Biondi, E., Zhu, W., Li, J., Williams, E. F., Zhan, Z. 2023; 9 (42): eadi9878

  Abstract

  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.

  View details for DOI 10.1126/sciadv.adi9878

  View details for PubMedID 37851798

  View details for PubMedCentralID PMC10584340

• The break of earthquake asperities imaged by distributed acoustic sensing. Nature Li, J., Kim, T., Lapusta, N., Biondi, E., Zhan, Z. 2023; 620 (7975): 800-806

  Abstract

  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.

  View details for DOI 10.1038/s41586-023-06227-w

  View details for PubMedID 37532935

  View details for PubMedCentralID 3606976

• Earthquake focal mechanisms with distributed acoustic sensing. Nature communications Li, J., Zhu, W., Biondi, E., Zhan, Z. 2023; 14 (1): 4181

  Abstract

  Earthquake focal mechanisms provide critical in-situ insights about the subsurface faulting geometry and stress state. For frequent small earthquakes (magnitude< 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.

  View details for DOI 10.1038/s41467-023-39639-3

  View details for PubMedID 37443136

  View details for PubMedCentralID PMC10345142

• Properties of a deep seismic waveguide measured with an optical fiber PHYSICAL REVIEW RESEARCH Lellouch, A., Biondi, E., Biondi, B. L., Luo, B., Jin, G., Meadows, M. A. 2021; 3 (1)

  View details for DOI 10.1103/PhysRevResearch.3.013164

  View details for Web of Science ID 000620022200002

• ADAPTATION OF A RANGE-DOPPLER ALGORITHM TO MULTISTATIC SIGNALS FROM ULTRASOUND ARRAYS Jakovljevic, M., Michaelides, R., Biondi, E., Herickhoff, C., Hyun, D., Zebker, H., Dahl, J., IEEE IEEE. 2021: 3269-3272

  View details for DOI 10.1109/IGARSS47720.2021.9554158

  View details for Web of Science ID 001250139803111

• Estimating Signal and Structured Noise in Ultrasound Data using Prediction-Error Filters Jennings, J., Jakovljevic, M., Biondi, E., Dahl, J., Biondi, B. edited by Byram, B. C., Ruiter, N. V. SPIE-INT SOC OPTICAL ENGINEERING. 2019

  View details for DOI 10.1117/12.2513514

  View details for Web of Science ID 000471826100024

• Nonstretch normal moveout through iterative partial correction and deconvolution. Geophysics Biondi, E., Stucchi, E., Mazzotti, A. 2014; 79 (4): V131-V141

  View details for DOI 10.1190/geo2013-0392.1

• Non-Stretch Fourth Order NMO through Iterative Partial Corrections and Deconvolution 75th EAGE Conference & Exhibition incorporating SPE EUROPEC 2013 Biondi, E., Stucchi, E., Mazzotti, A. 2013

  View details for DOI 10.3997/2214-4609.20130020