Emmanuel Soliman Mortel Garcia

@kyoto-u.ac.jp

Program-Specific Researcher, Earthquake Hazards Research Center, Disaster Prevention Research Institute
Kyoto University

Emmanuel Soliman Mortel Garcia


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https://researchid.co/esmgarcia
15

Scopus Publications

2920

Scholar Citations

10

Scholar h-index

11

Scholar i10-index

Scopus Publications

  • New insight into slow earthquake activities from continuous ocean bottom seismometers at the Guerrero seismic gap, Mexico
    Yanhan Chen, Yoshihiro Ito, Raymundo Plata-Martinez, Luis Antonio Dominguez, Shukei Ohyanagi, et al.
    Geophysical Journal International, 2025
    SUMMARY The Guerrero seismic gap in the Mexican subduction zone exhibits a slip behaviour distinct from that of adjacent segments, which typically experience large earthquakes. With the acquisition of offshore seismic data in this region and the discovery of shallow tectonic tremors, the study of slow earthquakes has gradually increased. This study presents the detection of tectonic tremors and low frequency earthquakes (LFEs) in the Guerrero seismic gap using a combination of a modified envelope cross-correlation method and a matched filter applied to ocean bottom seismometer data for a continuous two-year observational period. The modified envelope cross-correlation method was used to detect and locate tremors, and the matched filter technique enabled the detection of LFEs. These methods allowed for better constraints on the depths of the detected events, offering new insights into tremors and LFE activity offshore the Guerrero seismic gap. Our results show that the spatial distribution of these phenomena, along with seismicity, residual gravity anomalies and seafloor topography, suggests that a section of the shallow plate interface within the gap has experienced stable slip. This study builds on previous work by enhancing the detection and location accuracy of these slow earthquakes, contributing to a more comprehensive understanding of subduction dynamics in the region.
  • Deep plutonic bodies over low-frequency earthquakes revealed from receiver-side Green's functions
    Yasunori Sawaki, Yoshihiro Ito, Emmanuel Soliman M. Garcia, Ayumu Miyakawa, Takuo Shibutani
    Tectonophysics, 2024
  • Along-strike forearc and subducted upper slab structure beneath north Chile: Slow slip implications
    Pousali Mukherjee, Yoshihiro Ito, Kajaljyoti Borah, Admore Phindani Mpuang, Emmanuel Soliman Garcia, et al.
    Journal of South American Earth Sciences, 2024
  • Shear wave velocity structure at the Fukushima forearc region based on H/V analysis of ambient noise recordings by ocean bottom seismometers
    Atikul Haque Farazi, Yoshihiro Ito, Emmanuel Soliman M Garcia, Agostiny Marrios Lontsi, Francisco José Sánchez-Sesma, et al.
    Geophysical Journal International, 2023
    SUMMARYThis study presents the shear wave velocity (VS) structures of sedimentary sequences and a section of the upper crustal layer in the Fukushima forearc region of the Japan Trench subduction zone, which were obtained by analysing the horizontal-to-vertical (H/V) spectral ratios of ambient vibration records. The H/V curves were derived using 31 d of continuous seismic data from 3 broad-band and 16 short-period ocean bottom seismometer (OBS) stations. Using the broad-band data, H/V ratios from 0.01 to 10 Hz were derived, but the ratios below 0.1 Hz frequencies were unusually large and temporally unstable. Characterization of seismic noise energy from ∼1 yr of seismic data of three broad-band OBSs revealed variable and elevated energy conditions below 0.1 Hz due to typical long-period oceanic noise; we link these observations with the unstable H/V ratios below this frequency. Therefore, H/V analysis was performed in the frequency range of 0.1–10 Hz for both broad-band and short-period OBSs to obtain subsurface VS profiles. For the forward calculation of the H/V ratios in the inversion process, we used the recently developed ‘hvgeneralized’ method, which is based on the diffuse field assumption, and accounts for the water layer on top of stratified media. Moreover, available prior geological and geophysical information was utilized during the inversion of the H/V curves. We found that subsurface VS ranged from approximately 30 m s−1 at the seabed to approximately 4900 m s−1 at 7000 m below the sea floor (mbsf). Starting with the best model candidate at each OBS location, the effect of the water layer on the H/V curve in the deep ocean was investigated by comparing synthetic H/V curves with and without the water layer. The synthetic H/V analysis revealed that the water layer had a significant effect on H/V amplitudes at higher frequencies (>1 Hz), whereas comparatively little effect was observed at lower frequencies (<1 Hz). This study provides an empirical basis for H/V analysis using OBS data to determine VS down to several kilometres of sedimentary sequences to the upper crust with high-resolution.
  • Seafloor depth controls seismograph orientation uncertainty
    Yasunori Sawaki, Yusuke Yamashita, Shukei Ohyanagi, Emmanuel Soliman M Garcia, Aki Ito, et al.
    Geophysical Journal International, 2023
    SUMMARY This study evaluates the seafloor ambient noise environment that varies with the water depth based on a correction analysis of the horizontal sensor orientation for ocean-bottom seismographs. As ocean-bottom seismographs are mainly deployed as ‘free-fall’ installations, we have no information on which direction a horizontal sensor faces at the seafloor. An accurate sensor orientation is crucial for data processing based on seismic wavefields. Among several seismological approaches that use passive sources to correct the horizontal sensor azimuth, the particle motion of teleseismic Rayleigh waves is widely used for broad-band ocean-bottom seismographs. We performed seafloor seismic observations in the Hyuga-nada region at the western end of the Nankai subduction zone and deployed broad-band and short-period seismographs. However, studies have yet to investigate whether orientation correction via the Rayleigh-wave polarization method is valid for short-period data. The results of the Rayleigh wave method from our campaign observation data showed that the estimation uncertainty of short-period sensor orientations increased with a decreasing water depth; we observed a transition depth for the uncertainty at 2200–2600 m. The measurement quality, or the cross-correlation coefficient between the radial and Hilbert-transformed vertical components, also decreased at depths shallower than 2000 m. Moreover, an analysis of the noise power spectral densities showed that ambient noise levels during long periods (>10 s) increased with decreasing depth. Infragravity waves controlled vertical long-period noise levels, while ocean currents dominated horizontal long-period noise; both of these reduced the Rayleigh-wave signals as a function of environmental noise. Infragravity waves also likely distorted the Rayleigh waveforms. Both mechanisms contributed to the sudden rise in orientation uncertainty and low measurement quality at shallow stations (i.e. <2000 m). We confirmed that the variation in orientation uncertainty with the water depth can be used as an index for the ambient noise environment of the seafloor.
  • Shallow slow earthquakes to decipher future catastrophic earthquakes in the Guerrero seismic gap
    R. Plata-Martinez, S. Ide, M. Shinohara, E. S. Garcia, N. Mizuno, et al.
    Nature Communications, 2021
    The Guerrero seismic gap is presumed to be a major source of seismic and tsunami hazard along the Mexican subduction zone. Until recently, there were limited observations at the shallow portion of the plate interface offshore Guerrero, so we deployed instruments there to better characterize the extent of the seismogenic zone. Here we report the discovery of episodic shallow tremors and potential slow slip events in Guerrero offshore. Their distribution, together with that of repeating earthquakes, seismicity, residual gravity and bathymetry, suggest that a portion of the shallow plate interface in the gap undergoes stable slip. This mechanical condition may not only explain the long return period of large earthquakes inside the gap, but also reveals why the rupture from past M < 8 earthquakes on adjacent megathrust segments did not propagate into the gap to result in much larger events. However, dynamic rupture effects could drive one of these nearby earthquakes to break through the entire Guerrero seismic gap.
  • Water Depth Dependence of Long-Range Correlation in Nontidal Variations in Seafloor Pressure
    Tomohiro Inoue, Yoshihiro Ito, Laura M. Wallace, Yutaka Yoshikawa, Daisuke Inazu, et al.
    Geophysical Research Letters, 2021
    Isolating the source of nontidal oceanographic noise in seafloor pressure data is critical for improving the use of these data for seafloor geodetic applications. Residuals between nearby bottom pressure records have typically been used to remove the nontidal components, as these are largely common‐mode. To evaluate the similarities between pairs of observed bottom pressure records at a range of water depths, we calculate the standard deviations of the time series of residuals between data from all site pairs, installed in the Hikurangi subduction zone offshore New Zealand. We find that the magnitude of the standard deviation depends more on relative water depth than the distance between sites. This confirms the result of previous studies from Cascadia that nontidal components are more similar along isobaths even if the distance between sites is large. Furthermore, in order to reduce noises, the required depth difference between site pairs also varies with site depths.
  • Seafloor morphology along the active margin in Guerrero, Mexico: Probable earthquake implications
    Jan Černý, María Teresa Ramírez-Herrera, Emmanuel Soliman Garcia, Yoshihiro Ito
    Journal of South American Earth Sciences, 2020
  • Outer trench slope flexure and faulting at Pacific basin subduction zones
    Emmanuel Soliman M Garcia, David T Sandwell, Dan Bassett
    Geophysical Journal International, 2019
    SUMMARY Flexure and fracturing of the seafloor on the outer trench wall of subduction zones reflect bending of the lithosphere beyond its elastic limit. To investigate these inelastic processes, we have developed a full nonlinear inversion approach for estimating the bending moment, curvature and outer trench wall fracturing using shipboard bathymetry and satellite altimetry-derived gravity data as constraints. Bending moments and downward forces are imposed along curved trench axes and an iterative method is used to calculate the nonlinear response for 26 sites in the circum-Pacific region having seafloor age ranging from 15 to 148 Ma. We use standard thermal and yield strength envelope models to develop the nonlinear moment versus curvature relationship. Two coefficients of friction of 0.6 and 0.3 are considered and we find that the lower value provides a better overall fit to the data. The main result is that the lithosphere is nearly moment saturated at the trench axis. The effective elastic thickness of the plate on the outer trench slope is at least three times smaller than the elastic thickness of the plate before bending at the outer rise in agreement with previous studies. The average seafloor depth of the unbent plate in these 26 sites matches the Parsons & Sclater depth versus age model beyond 120 Ma. We also use the model to predict the offsets of normal faults on the outer trench walls and compare this with the horst and graben structures observed by multibeam surveys. The model with the lower coefficient of friction fits the fault offset data close to the trench axis. However, the model predicts significant fracturing of the lithosphere between 75 and 150 km away from the trench axis where no fracturing is observed. To reconcile these observations, we impose a thermoelastic pre-stress in the lithosphere prior to subduction. This pre-stress delays the onset of fracturing in better agreement with the data.
  • Deep embrittlement and complete rupture of the lithosphere during the M w 8.2 Tehuantepec earthquake
    Diego Melgar, Angel Ruiz-Angulo, Emmanuel Soliman Garcia, Marina Manea, Vlad. C. Manea, et al.
    Nature Geoscience, 2018
  • A seismogeodetic amphibious network in the Guerrero Seismic Gap, Mexico
    Víctor M. Cruz‐Atienza, Yoshihiro Ito, Vladimir Kostoglodov, Vala Hjörleifsdóttir, Arturo Iglesias, et al.
    Seismological Research Letters, 2018
  • An iterative spectral solution method for thin elastic plate flexure with variable rigidity
    Emmanuel S. Garcia, David T. Sandwell, Karen M. Luttrell
    Geophysical Journal International, 2015
  • New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure
    David T. Sandwell, R. Dietmar Müller, Walter H. F. Smith, Emmanuel Garcia, Richard Francis
    Science, 2014
  • Retracking cryosat-2, envisat and jason-1 radar altimetry waveforms for improved gravity field recovery
    Emmanuel S. Garcia, David T. Sandwell, Walter H.F. Smith
    Geophysical Journal International, 2014
  • Toward 1-mGal accuracy in global marine gravity from CryoSat-2, Envisat, and Jason-1
    David Sandwell, Emmanuel Garcia, Khalid Soofi, Paul Wessel, Michael Chandler, et al.
    Leading Edge, 2013

RECENT SCHOLAR PUBLICATIONS

  • New insight into slow earthquake activities from continuous ocean bottom seismometers at the Guerrero seismic gap, Mexico
    Y Chen, Y Ito, R Plata-Martinez, LA Dominguez, S Ohyanagi, ES Garcia, ...
    Geophysical Journal International 241 (1), 511-525 , 2025
    2025
  • Deep plutonic bodies over low-frequency earthquakes revealed from receiver-side Green's functions
    Y Sawaki, Y Ito, ESM Garcia, A Miyakawa, T Shibutani
    Tectonophysics 892, 230536 , 2024
    2024
    Citations: 1
  • Shear wave velocity structure at the Fukushima forearc region based on H/V analysis of ambient noise recordings by ocean bottom seismometers
    AH Farazi, Y Ito, ESM Garcia, AM Lontsi, FJ Sánchez-Sesma, A Jaramillo, ...
    Geophysical Journal International 233 (3), 1801-1820 , 2023
    2023
    Citations: 21
  • Seafloor depth controls seismograph orientation uncertainty
    Y Sawaki, Y Yamashita, S Ohyanagi, ESM Garcia, A Ito, H Sugioka, ...
    Geophysical Journal International 232 (2), 1376-1392 , 2023
    2023
    Citations: 6
  • Shallow slow earthquakes to decipher future catastrophic earthquakes in the Guerrero seismic gap
    R Plata-Martínez, S Ide, M Shinohara, ES Garcia, N Mizuno, ...
    Nature communications 12 (1), 3976 , 2021
    2021
    Citations: 71
  • Water Depth Dependence of Long‐Range Correlation in Nontidal Variations in Seafloor Pressure
    T Inoue, Y Ito, LM Wallace, Y Yoshikawa, D Inazu, ESM Garcia, ...
    Geophysical Research Letters 48 (8), e2020GL092173 , 2021
    2021
    Citations: 10
  • Seafloor morphology along the active margin in Guerrero, Mexico: Probable earthquake implications
    J Černý, MT Ramírez-Herrera, ES Garcia, Y Ito
    Journal of South American Earth Sciences 102, 102671 , 2020
    2020
    Citations: 11
  • Outer trench slope flexure and faulting at Pacific basin subduction zones
    ESM Garcia, DT Sandwell, D Bassett
    Geophysical Journal International 218 (1), 708-728 , 2019
    2019
    Citations: 37
  • Deep embrittlement and complete rupture of the lithosphere during the M w 8.2 Tehuantepec earthquake
    D Melgar, A Ruiz-Angulo, ES Garcia, M Manea, VC Manea, X Xu, ...
    Nature Geoscience 11 (12), 955-960 , 2018
    2018
    Citations: 65
  • A seismogeodetic amphibious network in the Guerrero seismic gap, Mexico
    VM Cruz‐Atienza, Y Ito, V Kostoglodov, V Hjörleifsdóttir, A Iglesias, J Tago, ...
    Seismological Research Letters 89 (4), 1435-1449 , 2018
    2018
    Citations: 32
  • An iterative spectral solution method for thin elastic plate flexure with variable rigidity
    ES Garcia, DT Sandwell, KM Luttrell
    Geophysical Journal International, ggu449 , 2014
    2014
    Citations: 28
  • New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure
    DT Sandwell, RD Müller, WHF Smith, E Garcia, R Francis
    science 346 (6205), 65-67 , 2014
    2014
    Citations: 2051
  • Retracking CryoSat-2, Envisat and Jason-1 radar altimetry waveforms for improved gravity field recovery
    ES Garcia, DT Sandwell, WHF Smith
    Geophysical Journal International 196 (3), 1402-1422 , 2014
    2014
    Citations: 162
  • Toward 1-mGal accuracy in global marine gravity from CryoSat-2, Envisat, and Jason-1
    D Sandwell, E Garcia, K Soofi, P Wessel, M Chandler, WHF Smith
    The Leading Edge 32 (8), 892-899 , 2013
    2013
    Citations: 425

MOST CITED SCHOLAR PUBLICATIONS

  • New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure
    DT Sandwell, RD Müller, WHF Smith, E Garcia, R Francis
    science 346 (6205), 65-67 , 2014
    2014
    Citations: 2051
  • Toward 1-mGal accuracy in global marine gravity from CryoSat-2, Envisat, and Jason-1
    D Sandwell, E Garcia, K Soofi, P Wessel, M Chandler, WHF Smith
    The Leading Edge 32 (8), 892-899 , 2013
    2013
    Citations: 425
  • Retracking CryoSat-2, Envisat and Jason-1 radar altimetry waveforms for improved gravity field recovery
    ES Garcia, DT Sandwell, WHF Smith
    Geophysical Journal International 196 (3), 1402-1422 , 2014
    2014
    Citations: 162
  • Shallow slow earthquakes to decipher future catastrophic earthquakes in the Guerrero seismic gap
    R Plata-Martínez, S Ide, M Shinohara, ES Garcia, N Mizuno, ...
    Nature communications 12 (1), 3976 , 2021
    2021
    Citations: 71
  • Deep embrittlement and complete rupture of the lithosphere during the M w 8.2 Tehuantepec earthquake
    D Melgar, A Ruiz-Angulo, ES Garcia, M Manea, VC Manea, X Xu, ...
    Nature Geoscience 11 (12), 955-960 , 2018
    2018
    Citations: 65
  • Outer trench slope flexure and faulting at Pacific basin subduction zones
    ESM Garcia, DT Sandwell, D Bassett
    Geophysical Journal International 218 (1), 708-728 , 2019
    2019
    Citations: 37
  • A seismogeodetic amphibious network in the Guerrero seismic gap, Mexico
    VM Cruz‐Atienza, Y Ito, V Kostoglodov, V Hjörleifsdóttir, A Iglesias, J Tago, ...
    Seismological Research Letters 89 (4), 1435-1449 , 2018
    2018
    Citations: 32
  • An iterative spectral solution method for thin elastic plate flexure with variable rigidity
    ES Garcia, DT Sandwell, KM Luttrell
    Geophysical Journal International, ggu449 , 2014
    2014
    Citations: 28
  • Shear wave velocity structure at the Fukushima forearc region based on H/V analysis of ambient noise recordings by ocean bottom seismometers
    AH Farazi, Y Ito, ESM Garcia, AM Lontsi, FJ Sánchez-Sesma, A Jaramillo, ...
    Geophysical Journal International 233 (3), 1801-1820 , 2023
    2023
    Citations: 21
  • Seafloor morphology along the active margin in Guerrero, Mexico: Probable earthquake implications
    J Černý, MT Ramírez-Herrera, ES Garcia, Y Ito
    Journal of South American Earth Sciences 102, 102671 , 2020
    2020
    Citations: 11
  • Water Depth Dependence of Long‐Range Correlation in Nontidal Variations in Seafloor Pressure
    T Inoue, Y Ito, LM Wallace, Y Yoshikawa, D Inazu, ESM Garcia, ...
    Geophysical Research Letters 48 (8), e2020GL092173 , 2021
    2021
    Citations: 10
  • Seafloor depth controls seismograph orientation uncertainty
    Y Sawaki, Y Yamashita, S Ohyanagi, ESM Garcia, A Ito, H Sugioka, ...
    Geophysical Journal International 232 (2), 1376-1392 , 2023
    2023
    Citations: 6
  • Deep plutonic bodies over low-frequency earthquakes revealed from receiver-side Green's functions
    Y Sawaki, Y Ito, ESM Garcia, A Miyakawa, T Shibutani
    Tectonophysics 892, 230536 , 2024
    2024
    Citations: 1
  • New insight into slow earthquake activities from continuous ocean bottom seismometers at the Guerrero seismic gap, Mexico
    Y Chen, Y Ito, R Plata-Martinez, LA Dominguez, S Ohyanagi, ES Garcia, ...
    Geophysical Journal International 241 (1), 511-525 , 2025
    2025