Hideo Aochi

Hideo Aochi
French Geological Survey | BRGM · Direction Risques et Prévention

PhD

About

149
Publications
24,579
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1,724
Citations

Publications

Publications (149)
Article
Full-text available
We compare ground motions simulated from dynamic rupture scenarios, for the seismic gap along the North Anatolian Fault under the Marmara Sea (Turkey), to estimates from empirical ground motion prediction equations (GMPEs). Ground motions are simulated using a finite difference method and a 3D model of the local crustal structure. They are analyzed...
Article
Full-text available
This paper reports asymmetric features of normal and reverse faulting from the point of view of earthquake dynamics. It is assumed that the fault's strength is governed by Coulomb friction, namely depending on normal stress, and numerical simulations are carried out using a boundary domain method, a hybrid coupling between the boundary integral equ...
Article
Full-text available
Numerical simulations are carried out for the dynamic rupture and wave propagation process of the 24th August 2016 ML 6.0 Amatrice, Italy, earthquake, using a boundary domain method (BDM), a hybrid method of boundary integral equation and finite difference methods. Dynamic rupture parameters of two seismogenic asperities are searched by iterative s...
Article
Full-text available
We apply kinematic and dynamic modeling to the 2015 Mw8.3 Illapel, Chile, earthquake constrained by continuous high-rate GPS and strong motion data. Kinematic inversion by elliptical patches allows us to rapidly outline the ruptured area with different time windows and frequency ranges. The preferred solution indicates that the main large patch in...
Article
The seismicity evolution in Oklahoma between 2010 and 2018 is analyzed systematically using an epidemic-type aftershock sequence model. To retrieve the nonstationary seismicity component, we systematically use a moving window of 200 events, each within a radius of 20 km at grid points spaced every 0.2°. Fifty-three areas in total are selected for o...
Preprint
The Mw 4.9 earthquake of 11 November 2019 at Le Teil (France) occurred at a very shallow depth (about 1 km) inducing the surface rupture of La Rouvière fault, nearby of a limestone quarry. Thanks to satellite differential interferometry, we detected the existence of the secondary surface rupture of the quasi-parallel Bayne Rocherenard fault. A newl...
Article
Full-text available
We studied the correlation between seismicity and the water table level in an abandoned coal mine (Bouches-du-Rhône, France), closed in 2003, where groundwater has been pumped out since 2010 to prevent underground flooding. Microseismic-ity was first felt by the population in 2010 and a strongly felt seismic swarm occurred in November 2012. The ori...
Article
Properties of earthquake source physics can be inferred from the comparison between seismic observations and results of dynamic rupture models. Although simple self-similar rupture models naturally explain the space and time observations at the scale of the whole earthquake, several observational studies based on the analysis of source time functio...
Presentation
Full-text available
Seminar presentation given on line on the 17th December 2021, originally in Japanese, here in English version. See more details in the cited papers.
Conference Paper
Full-text available
On 11 November 2019, a 5 magnitude earthquake occurred in southeast France at Le Teil, close to the Rhone river. This seismic event is the strongest earthquake ever felt in France since the Arette (Pyrenees) earthquake in 1967. By using an updated 3D geological model, we focus this work on the comparison of the effect of hydraulic recharge linked t...
Article
Full-text available
Propagation of long-period ground motion in sedimentary basins has been a subject of great interest among seismologists and engineers. Intense long-period ground motions consist primarily of surface waves that get trapped or generated locally as seismic energy travels through sedimentary deposits. In the present work, we investigate the propagation...
Article
Full-text available
The devastating Mw 7.1 Haiti earthquake in 2010 was accompanied by local tsunamis that caused fatalities and damage to coastal infrastructure. Some were triggered by slope failures of river deltas in the close vicinity of the epicenter, while others, 30 to 50 km to the north across the Bay of Gonâve, are well explained by the reverse component of c...
Presentation
The 6 July 2019 MW 7.1 Ridgecrest earthquake event originated north north-east of Los Angeles, at a distance of ~150 km as a result of shallow strike slip faulting in the crust of the North America plate. Using a very effective tool, referred to as the Normalized Inner Product (NIP), we detect, identify and extract surface wave energy propagating i...
Preprint
Full-text available
Abstract. The devastating M<sub>w</sub> 7, 2010, Haiti earthquake was accompanied by local tsunamis that caused fatalities and damage to coastal infrastructure. Some were triggered by slope failures of river deltas in close vicinity of the epicenter, while others, 30 to 50 km to the north across the Bay of Gonâve, are well explained by the reverse...
Conference Paper
Recent events have allowed the observation of the effects of long-period motions on large-scale structures in Japan, and their devastating consequences. In this work we investigate the generation of surface waves in the basin of Nagoya (Nobi plain) in Japan, from seismograms of the K-net network, including recordings of the Mw 9.0 2011 Tohoku earth...
Article
Full-text available
Acquisitions of the Sentinel-1 satellite are processed and comprehensively analyzed to investigate the ground displacement during a three-year period above a double gas storage site (Lussagnet and Izaute) in Southwestern France. Despite quite low vertical displacements (between 4 and 8 mm) compared to the noise level, the cyclic motion reflects the...
Preprint
Acquisitions of the Sentinel-1 satellite are processed and comprehensively analyzed to investigate the ground displacement during a 3-year period above a gas storage site in Southwestern France. Despite quite low vertical displacements (between 4 and 8 mm) compared to the noise level, the local displacements reflects the variations due to charge an...
Article
Full-text available
The source mechanism of the ML 4.0 25 April 2016 Lacq earthquake (Aquitaine Basin, South-West France) is analyzed from the available public data and discussed with respect to the geometry of the nearby Lacq gas field. It is one of the biggest earthquakes in the area in the past few decades of gas extraction and the biggest after the end of gas expl...
Article
Full-text available
The Cholame section of the San Andreas Fault (SAF), considered locked since 1857, remains little studied using geodetic methods. In this study, we propose to use Interferometric Synthetic Aperture Radar (InSAR) to contribute to the improvement of the knowledge of this section of the SAF. In particular, the objective of this work is to provide a des...
Article
Full-text available
This study focuses on the shallow deformation that occurred during the 5 years following the Parkfield earthquake (28/09/2004, Mw 6, San Andreas Fault, California). We use Synthetic Aperture Radar interferometry (InSAR) to provide precise measurements of transient deformations after the Parkfield earthquake between 2005 and 2010. We propose a metho...
Article
Full-text available
A problem of quasi-static growth of an arbitrary shaped-crack along an interface requires many times of iterations not only for finding a spatial distribution of discontinuity but also for determining the crack tip. This is crucial when refining model resolution and also when the phenomena progresses quickly from one step to another. We propose a m...
Article
Full-text available
Quasi-static numerical simulations of slip along a fault interface characterized by multiscale heterogeneity (fractal patch model) are carried out under the assumption that the characteristic distance in the slip-dependent frictional law is scale-dependent. We also consider slip-dependent stress accumulation on patches prior to the weakening proces...
Article
Full-text available
We utilize L-band interferometric synthetic aperture radar (InSAR) data in this study to retrieve a ground velocity map for the near field of the Ganos section of the north Anatolian fault (NAF) zone. The segmentation and creep distribution of this section, which last ruptured in 1912 to generate a moment magnitude (Mw)7.3 earthquake, remains incom...
Data
Raw data for cross GF velocity profiles. Surface displacement measured on the basis of the stacked profiles within boxe “A” in Fig 2. (XLSX)
Data
Example interferograms on the study region. From the 39 coherent ALOS PALSAR interferograms used in this study, we show examples of four representative interferograms spanning 690 days, 644 days, 322 days and 92 days. The full PALSAR frame is shown. The red rectangle represents the common area covering the GF (Figs 1 and 2) where the SAR signal is...
Data
Raw data for cross GF velocity profiles. Surface displacement measured on the basis of the stacked profiles within boxe “B” in Fig 2. (XLSX)
Article
Full-text available
The city of Istanbul is characterized by one of the highest levels of seismic risk in the Mediterranean region. An important source of such increased risk is the high probability of large earthquake occurrence during the coming years, which stands at about 65% likelihood owing to the existing seismic gap and the post-1999 earthquake stress transfer...
Poster
Full-text available
It is crucial to estimate quantitatively the ground motions for the expected earthquake scenarios especially in the regions where the seismic potential in the near future is highly recognized. Istanbul and its surrounding areas are warned for the future high seismic risk in the Euro-Mediterranean region, especially pronounced after the 1999 Izmit a...
Article
The injection or extraction of fluids in the subsurface for energy purposes (e.g. geothermal exploitation, CO2 storage or geological energy storage) requires both the operation efficiency and the associated environmental risks to be assessed and controlled. Even though scientific and technological progress allows more accurate 3D modelling of the s...
Article
Full-text available
We study the ground motion simulations based on three finite-source models for the 2007 Mw6.6 Niigata Chuetsu-oki, Japan, earthquake in order to discuss the performance of the input ground motion estimations for the near-field seismic hazard analysis. The three models include a kinematic source inverted from the regional accelerations, a dynamic so...
Article
Since a few decades volcanic Long Period (LP) events have been recorded on many active volcanoes and their study has been recognized as an important tool to characterize volcanic activity. LP event analyses through moment tensor (MT) inversions have led to kinematic descriptions of various source mechanisms. The main challenge in these inversions i...
Article
During the 20th century, a series of devastating earthquakes occurred along the North Anatolian Fault. These generally propagated westwards, such that the main fault segment beneath the Marmara Sea appears as a seismic gap. For the nearby megacity Istanbul, rapid seismic hazard assessment is currently of great importance. A key issue is how a stron...
Article
Recent studies have shown that repeatable travel-path terms make a high contribution to the overall variability in earthquake ground motions. Having maps of such terms available for a given recording site would, theoretically, allow removal of this component from the aleatory variability of ground-motion models. The assessment of such travel-path t...
Article
The large processing requirements of seismic wave propagation simulations make High Performance Computing (HPC) architectures a natural choice for their execution. However, to keep both the current pace of performance improvements and the power consumption under a strict power budget, HPC systems must be more energy efficient than ever. As a respon...
Presentation
Full-text available
Variability estimation in ground motion around Istanbul based on the probabilistic dynamic rupture scenarios along the North Anatolian fault
Article
We perform numerical simulations of dynamic rupture processes along the North Anatolian fault in the Sea of Marmara, which poses a high risk to the nearby city of Istanbul. Several fault geometry models, nucleation points, and initial stress states are tested. The likelihood of each earthquake scenario is evaluated, and a probabilistic assessment o...
Article
Full-text available
Reactive flow at depth (either related to underground activities, like enhancement of hydrocarbon recovery and CO 2 storage, or to natural flow like in hydrothermal zones) can alter fractures’ topography, which might in turn change their seismic responses. Depending on the flow and reaction rates, instability of the dissolution front can lead to a...
Article
The mechanisms controlling rupture propagation between fault segments during an earthquake are key to the hazard posed by fault systemsThe mechanisms controlling rupture propagation between fault segments during a large earthquake are key to the hazard posed by fault systems. Rupture initiation on a fault segmentsmaller fault sometimes transfers to...
Conference Paper
Full-text available
Geostatistical methods provide a powerful tool to understand the complexity of data arising from Earth sciences. Since the mid 70's, this numerical approach is widely used to understand the spatial variation of natural phenomena in various domains like Oil and Gas, Mining or Environmental Industries. Considering the huge amount of data available, s...
Article
Full-text available
We have carried out numerical simulations of seismic ground motion radiating from a mega-earthquake whose rupture process is governed by a multi-scale heterogeneous distribution of fracture energy. The observed complexity of the Mw 9.0 2011 Tohoku-Oki earthquake can be explained by such heterogeneities with fractal patches (size and number), even w...
Article
The Sea of Marmara, Turkey, is one of the regions of the highest seismic potential in the world, and therefore the risk prevention is one of the major concerns of the country, in particular for the biggest town of the area, Istanbul. The disaster from the nearby 1999 Izmit, Duzce earthquakes is unforgettable, and the seismologists have been studyin...
Article
The spatio-temporal evolution of stress state is analyzed during the 2009-2010 Slow Slip Event (SSE) of Guerrero, Mexico, based on the kinematic inversion results and using an integral expression for stress changes. A linear slip weakening behavior is generally observed during the SSE with an average slope of −0.5±0.2 MPa/m regardless the perturbat...
Article
We carry out simulations of seismic wave propagation in anelastic media in order to study the relative importance of source parameters as well as viscoelastic structures in affecting the decay of the ground motions. First, we verify the efficiency of the implementation in a finite difference code of two coarse-grain memory variables methods to mode...
Article
Full-text available
Earthquakes occur in a complex hierarchical fault system, meaning that a realistic mechanically-consistent model is required to describe heterogeneity simply and over a wide scale. We developed a simple conceptual mechanical model using fractal circular patches associated with fracture energy on a fault plane. This model explains the complexity and...
Article
The Marmara region (Turkey) along the North Anatolian fault is known as a high potential of large earthquakes in the next decades. For the purpose of seismic hazard/risk evaluation, kinematic and dynamic source models have been proposed (e.g. Oglesby and Mai, GJI, 2012). In general, the simulated earthquake scenarios depend on the hypothesis and ca...
Article
Long period seismic events observed under many volcanoes are often interpreted in relation to any fluid-filled resonator. The kinematic mechanisms have been also studied seismologically in terms of seismic moment, and some of them indicate the geometry of a 'tensile' crack. In Volcanology, Chouet (1986) first solved the elasto-dynamic equations cou...
Article
Guerrero, in Mexico, is one of the subduction zones where long term slow slip events (SSEs) have been observed recurrently. Understanding the mechanics of these events is important to determine their role in the seismic cycle. SSEs in Guerrero have been found to have the same characteristics, along the interface of subduction, as classical earthqua...
Article
The kinematic rupture process of the 2011 Mw 9.0 Tohoku earthquake is inverted with an elliptical-patches method, using a genetic algorithm, for the purpose of rapid and robust estimation of the source parameters of a mega-earthquake. We use the ground-displacement field provided by a continuous GPS network and the ground-velocity field recorded by...
Article
Full-text available
Enhanced geothermal systems (EGS) are an attractive source of low-carbon electricity and heating. Consequently, a number of tests of this technology have been made during the past couple of decades, and various projects are being planned or under development. EGS work by the injection of fluid into deep boreholes to increase permeability and hence...
Conference Paper
Full-text available
Understanding the wave propagation with respect to the structure of the Earth lies at the heart of many analysis both in the oil and gas industry and for quantitative seismic hazard assessment. One of the most widely used techniques to solve the elastodynamics equation is the finite difference method because of its simplicity and numerical efficien...
Article
In this paper, we develop a system of equations describing fluid migration, fault rheology, fault thickness evolution and shear rupture during a seismic cycle, triggered either by tectonic loading or by fluid injection. Assuming that the phenomena predominantly take place on a single fault described as a finite permeable zone of variable width, we...
Article
Full-text available
Seismic waves radiated from an earthquake propagate in the Earth and the ground shaking is felt and recorded at (or near) the ground surface. Understanding the wave propagation with respect to the Earth's structure and the earthquake mechanisms is one of the main objectives of seismology, and predicting the strong ground shaking for moderate and la...
Article
It has been proposed that earthquake complexity can be described by multi-scale heterogeneity in fracture energy of the fault interface (Ide and Aochi, JGR, 2005). The 2011 Tohoku earthquake revealed us such multi-scalability of the fault heterogeneity, seemingly a cascade-rupture mode (Aochi and Ide, EPS, 2011; Ide and Aochi, accepted in Tectonoph...
Article
A number of studies have documented the complex rupture process of the Mw9.0 March 11, 2011 Tohoku-Oki earthquake, which is characterized by different stages of rupture, including a large delayed slip near the trench and multiple high-frequency ruptures along the down-dip edge of the seismogenic zone. In this study, a multiscale circular patch mode...
Article
Earthquake fault heterogeneity is often studied on a set of subfaults in kinematic inversion, while it is sometimes described with spatially localized geometry. Aochi and Ide (EPS, 2011) and Ide and Aochi (submitted to Pageoph and AGU, 2012) apply a concept of multi-scale heterogeneity to simulate the dynamic rupture process of the 2011 Tohoku-oki...
Article
The extreme ground motion in the near field is actually an engineering interest, because important damages are observed even if any standard construction code is applied. Such extreme ground motion is identified by a PGV (Peak Vround Velocity) more than 100 cm/s or a PGA (Peak Ground Acceleration) more than 800 gal (cm/s/s), for instance (Kawase, J...
Article
Full-text available
We used the ability of InSAR technique to provide precise displacement map in line of sight to characterise the post-seismic deformation following the 28 September 2004 (Mw 6) Parkfield earthquake between 2005 and 2010 (San Andreas Fault, California). Measuring the post-seismic displacement distribution and its spatio-temporal evolution is one of t...
Conference Paper
Full-text available
Simulation of large scale seismic wave propagation is an important tool in seismology for efficient strong motion analysis and risk mitigation. Being particularly CPU-consuming, this three-dimensional problem has been early ported on graphics cards to improve the performance by several order of magnitude. Scientific visualization of data produced b...
Conference Paper
Full-text available
For the past two decades, the combination between the boundary integral equation method (BIEM) and the finite difference method (FDM) has provided a powerful approach for simulating the dynamic rupture process along a complex fault system and the resultant seismic wave radiation and propagation for the purpose of un