Édouard Kaminski - Academia.edu (original) (raw)

Papers by Édouard Kaminski

2008 Second Workshop on Use of Remote Sensing Techniques for Monitoring Volcanoes and Seismogenic Areas, 2008

ABSTRACT Due to its high eruptive activity, Piton de La Fournaise is an ideal case study to follo... more ABSTRACT Due to its high eruptive activity, Piton de La Fournaise is an ideal case study to follow ground deformation associated with eruptive activity. Ground deformation is monitored in the field by the Volcanological Observatory of Piton de La Fournaise. GPS data reveal the presence of two time scales of ground deformation: (1) large short-term displacements (up to 20�?103 mm d-1 ) monitored a few min to hours prior each eruption (2) and since 2000, small long-term ground displacements recorded during pre-eruptive unrests (0.4-0.7 mm d-1 of summit inflation) and after major distal eruptions (0.3-1.3 mm d-1 of summit deflation). The large GPS dataset available to follow the eruptive cycles is particularly useful to validate the remote sensing data as shown by the Globvolcano project. The good correlation between GPS and PSInSAR data recorded during pre-eruptive unrest periods allowed us to validate the ground deformation mapping using PSInSAR data at Piton de La Fournaise. The combination of PSInSar and GPS data, in the future, will give us complementary data to investigate the ground deformation associated with eruptive cycles on a larger space scale and thus better constrain the deformation sources.

The Earth's Heterogeneous Mantle, 2015

Earth composition models rely on three types of information: petrological sampling, geophysical s... more Earth composition models rely on three types of information: petrological sampling, geophysical sounding, and cosmochemical constraints. The relative input of a given category of information changes with the depth of the considered Earth’s layer. The constraints brought by the petrological approach are dominant for the upperparts of the Mantle, whereas geophysical constraints play a crucial role for estimating deep Earth (lower mantle and core) composition. Since a direct sampling of the deep Earth is not possible, chemical constraints are mainly brought by the composition of primitive chondrites. In the more general approach, chondritic refractory lithophile elements (RLE) ratios are used to infer their content in the mantle. In addition, the family of “E-Earth models ” uses not only chondritic RLE ratios, but also the bulk composition of a particular family of chondrites: enstatite (EH , EL ) chondrites. These chondrites are the closest to the Earth in terms of isotopic composition as well as redox state and can be used to infer the composition of the deep Earth following a mass balance approach. In this paper, we first review the main characteristics of E-Chondrites in relation to the isotopic and redox characteristics of the Earth. We then present the main steps of the determination of the Earth composition based on a generic model of E-chondrites, and we then expand our previous results to the content of some minor and major trace elements in the deep mantle. The general characteristics of E-Earth compositions and their consequences for Earth differentiation and dynamics are discussed, and paths for further improvements of the model are presented.

The use of seismic anisotropy to image and constrain upper mantle flow is usually based on the as... more The use of seismic anisotropy to image and constrain upper mantle flow is usually based on the assumption that the direction of fast propagation of seismic waves is the same as the flow direction. Laboratory experiments showed however that when melt is present, it is rather the direction of slow propagation that aligns with the flow direction. A quantitative description of the effect of melt on the development of lattice preferred orientation (LPO) and its implications for the interpretation of anisotropy is thus required to assess the predictive power of a given geodynamic model. Here I show that taking into account strain partitioning associated with melt segregation in the modeling yields a good agreement with experimental results. Implementing strain partitioning in a test flow demonstrates that the effect of melt is mainly local and has a limited effect on seismic anisotropy. Water-induced texture, melt-filled cracks or channelized flow, might better account for seismic observa...

Large-scale measurements of seismic anisotropy in the Pacific ocean show a global alignment of fa... more Large-scale measurements of seismic anisotropy in the Pacific ocean show a global alignment of fast directions with the motion of the Pacific plate, but significant disturbances occur near hotspots such as Hawaii. To understand better what such observations tell us about mantle flow beneath Hawaii, we have performed a direct numerical calculation of the anisotropy due to the steady flow of an ascending thermal plume interacting with a moving lithosphere. A 3-D multigrid code provides the flow field, from which the evolution of olivine lattice preferred orientation (LPO) is calculated using the plastic flow/recrystallization model of Kaminski and Ribe (Earth. Planet. Sci. Lett. 189, 253-267, 2001.) The resulting LPO field is then used to calculate the anisotropic elastic tensor Cijkl throughout the model domain. The LPO within the advected tail of the plume displays strong vertical and horizontal variations between 80 and 150 km depth, and the mean fast axis orientation e} is not sys...

ABSTRACT The Hawaiian volcanism is thought to be generated by a thermal mantle plume. A 3-D conve... more ABSTRACT The Hawaiian volcanism is thought to be generated by a thermal mantle plume. A 3-D convection code using the hybrid spectral/finite difference technique of Christensen & Harder (1991) describes the interaction of the Hawaiian plume with the moving Pacific lithosphere (Ribe & Christensen, 1994). A steady state flow field solution allows to calculate the velocity gradient field and the path of rocks. This can be used to integrate along streamlines either the finite deformation or the Lattice Preferred Orientation (LPO) of upper mantle minerals (olivine, orthopyroxene). The code D-Rex describing the deformation of a mineral aggregate by dislocation creep and dynamic recrystallization provides the necessary tool to obtain the LPO (Kaminski, Ribe & Browaeys, 2004). The equivalent elastic tensor at each position of the model is calculated using both the Orientation Distribution Function related to the LPO and tabulated elastic tensor of minerals. The tensor is then reduced to its transverse isotropic part by decomposition into different symmetry class components (Browaeys & Chevrot, 2004). The convolution of the sensitivity kernels for shear wave splitting in a transverse isotropic medium (Favier & Chevrot, 2004) with the 3-D distribution model of transverse isotropy gives variation of the splitting intensity I(alpha ) with the backazimuth alpha of the teleseismic wave. The splitting intensity can be related to the parameters of classical ray theory (time delay delta t and fast axis direction phi 0) by the relationship I(alpha )=delta t sin2 (alpha -phi 0). A comparison between the fast axis orientations in the 3-D model and the fast direction deduced from the classical expression of I(alpha ) is done. It shows that in regions where the wave propagates through inhomogeneous anisotropic properties compare to the typical wavelength of a teleseismic wave (i.e. lambda ˜ 50 km), there is no simple relation between the seismic anisotropy observations and the underlying anisotropic structure in the upper mantle.

The Ocean Island Basalts (OIB) have specific geochemical signatures (large scattering in the 3He/... more The Ocean Island Basalts (OIB) have specific geochemical signatures (large scattering in the 3He/4He ratio, large 40Ar/36Ar ratio), which suggest that they originate from several reservoirs, one of which should be undegassed. It was long assumed that the undegassed reservoir is hidden in the lower mantle (or is the lower mantle itself), but the discovery of slabs penetrating in the deep mantle invalidated this hypothesis. This apparent contradiction can however be removed assuming that the undegassed reservoir consists of domes of chemically differentiated material located in the deep mantle, as revealed by numerical experiments of thermo-chemical convection we recently conducted. These experiments showed that: (1) a strong thermal viscosity contrast create and maintain large pools of dense material at the bottom of the system; and (2) an endothermic phase transition at 660-km depth prevents the dense primitive material to massively flow into the upper part of the system. As a result, the secondary thermal plumes that are generated at the top of the pools of dense material dramatically thin at the 660 km boundary and entrain only a very small amount of dense material upwards. Reservoirs of dense primitive material (resulting, e.g., from early differentiation) can thus survive for durations comparable to the age of the Earth, and small amounts of this dense primitive material is periodically injected in the upper mantle and transported to the surface. We run additional experiments of thermo-chemical convection, in which we varied the chemical density contrast between the dense primitive and regular materials (measured by the buoyancy ratio B) and the Clapeyron slope at 660 km (Gamma660), and for each experiment, we quantified the fraction of dense primitive material that is transported by the thinned plumes and compared it to available constraints from geochemistry. We found that the mass fraction of dense material transported by secondary plumes (xPM) decreases with increasing B, and decreases with decreasing Gamma660. Taking Gamma660 = -1.0 MPa/K, which is a conservative value, xPM varies between 0.04 and 0.21 for a reasonable range of buoyancy ratio (0.25 >= B >= 0.15). Taking B = 0.2 (equivalent, in our models, to a chemical density contrast of 80 kg/m3), xPM varies between 0.17 and 0.05 for values of Gamma660 between -0.5 and -3.0 MPa/K. Assuming that the primitive reservoir's helium ratio ([3He/4He]PM) is around 12500, mass balance geochemical calculations indicate that the fraction of primitive material entrained in the secondary plumes should not exceed 0.1. Within the current uncertainties in [3He/4He]PM, the fraction of primitive material that should not be exceeded in plumes may be up to 0.2. This is larger than the fraction of primitive material entrained by secondary plumes in models with reasonable values of Gamma660 and B for the Earth's mantle. Thus, models of thermo-chemical convection that include an endothermic phase transition at 660 km, a large thermal viscosity contrast, and a moderate chemical density contrast, qualitatively and quantitatively support the hypothesis that OIB partially sample a reservoir of undegassed, dense primitive material located in the lower mantle.

From a compositional, dynamical, and structural standpoint, subduction zones are arguably Earth&a... more From a compositional, dynamical, and structural standpoint, subduction zones are arguably Earth's most complex tectonic setting. Significant uncertainty remains regarding the extent of coupling between lithospheric plates and surrounding mantle, as well as the extent to which the mantle wedge is hydrated in subduction systems. A key observation used to address these issues is measurements of seismic anisotropy, which while

Frontiers in Earth Science

In the last 70 years, geophysics has established that the Earth’s outer core is an FeNi alloy con... more In the last 70 years, geophysics has established that the Earth’s outer core is an FeNi alloy containing a few percent of light elements, whose nature and amount remain controversial. Besides the classical combinations of silicon and oxygen, hydrogen has been advocated as the only light element that could account alone for both the core density and velocity profiles. Here we show how this question can be addressed from an independent viewpoint, by exploiting the tomographic information provided by atmospheric neutrinos, weakly-interacting particles produced in the atmosphere and constantly traversing the Earth. We evaluate the potential of the upcoming generation of atmospheric neutrino detectors for such a measurement, showing that they could efficiently detect the presence of 1 wt% hydrogen in the Earth’s core in 50 years of concomitant data taking. We then identify the main requirements for a next-generation detector to perform this measurement in a few years timescale, with the ...

… 2010, held 2-7 May …, 2010

The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Sp... more The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate ...

ESA Living Planet Symposium, Dec 1, 2010

Riassunto GlobVolcano è un progetto finanziato dall'ESA (European Space Agency) nell'ambito del p... more Riassunto GlobVolcano è un progetto finanziato dall'ESA (European Space Agency) nell'ambito del programma Data User Element (DUE). Il progetto è finalizzato alla realizzazione e dimostrazione di un servizio a scala globale, basato su dati di osservazione della terra (EO Earth Observation), a supporto delle attività degli Osservatori Vulcanologici e/o Enti di Protezione Civile incaricati della sorveglianza in aree vulcaniche attive. Nel corso della prima fase del progetto il sistema informativo è stato progettato, sviluppato e validato. La validazione è stata effettuata per un numero limitato di aree test (Colima in Messico,

… 2010, held 2-7 May …, 2010

The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Sp... more The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate ...

2008 Second Workshop on Use of Remote Sensing Techniques for Monitoring Volcanoes and Seismogenic Areas, 2008

ABSTRACT Due to its high eruptive activity, Piton de La Fournaise is an ideal case study to follo... more ABSTRACT Due to its high eruptive activity, Piton de La Fournaise is an ideal case study to follow ground deformation associated with eruptive activity. Ground deformation is monitored in the field by the Volcanological Observatory of Piton de La Fournaise. GPS data reveal the presence of two time scales of ground deformation: (1) large short-term displacements (up to 20�?103 mm d-1 ) monitored a few min to hours prior each eruption (2) and since 2000, small long-term ground displacements recorded during pre-eruptive unrests (0.4-0.7 mm d-1 of summit inflation) and after major distal eruptions (0.3-1.3 mm d-1 of summit deflation). The large GPS dataset available to follow the eruptive cycles is particularly useful to validate the remote sensing data as shown by the Globvolcano project. The good correlation between GPS and PSInSAR data recorded during pre-eruptive unrest periods allowed us to validate the ground deformation mapping using PSInSAR data at Piton de La Fournaise. The combination of PSInSar and GPS data, in the future, will give us complementary data to investigate the ground deformation associated with eruptive cycles on a larger space scale and thus better constrain the deformation sources.

The Earth's Heterogeneous Mantle, 2015

Earth composition models rely on three types of information: petrological sampling, geophysical s... more Earth composition models rely on three types of information: petrological sampling, geophysical sounding, and cosmochemical constraints. The relative input of a given category of information changes with the depth of the considered Earth’s layer. The constraints brought by the petrological approach are dominant for the upperparts of the Mantle, whereas geophysical constraints play a crucial role for estimating deep Earth (lower mantle and core) composition. Since a direct sampling of the deep Earth is not possible, chemical constraints are mainly brought by the composition of primitive chondrites. In the more general approach, chondritic refractory lithophile elements (RLE) ratios are used to infer their content in the mantle. In addition, the family of “E-Earth models ” uses not only chondritic RLE ratios, but also the bulk composition of a particular family of chondrites: enstatite (EH , EL ) chondrites. These chondrites are the closest to the Earth in terms of isotopic composition as well as redox state and can be used to infer the composition of the deep Earth following a mass balance approach. In this paper, we first review the main characteristics of E-Chondrites in relation to the isotopic and redox characteristics of the Earth. We then present the main steps of the determination of the Earth composition based on a generic model of E-chondrites, and we then expand our previous results to the content of some minor and major trace elements in the deep mantle. The general characteristics of E-Earth compositions and their consequences for Earth differentiation and dynamics are discussed, and paths for further improvements of the model are presented.

The use of seismic anisotropy to image and constrain upper mantle flow is usually based on the as... more The use of seismic anisotropy to image and constrain upper mantle flow is usually based on the assumption that the direction of fast propagation of seismic waves is the same as the flow direction. Laboratory experiments showed however that when melt is present, it is rather the direction of slow propagation that aligns with the flow direction. A quantitative description of the effect of melt on the development of lattice preferred orientation (LPO) and its implications for the interpretation of anisotropy is thus required to assess the predictive power of a given geodynamic model. Here I show that taking into account strain partitioning associated with melt segregation in the modeling yields a good agreement with experimental results. Implementing strain partitioning in a test flow demonstrates that the effect of melt is mainly local and has a limited effect on seismic anisotropy. Water-induced texture, melt-filled cracks or channelized flow, might better account for seismic observa...

Large-scale measurements of seismic anisotropy in the Pacific ocean show a global alignment of fa... more Large-scale measurements of seismic anisotropy in the Pacific ocean show a global alignment of fast directions with the motion of the Pacific plate, but significant disturbances occur near hotspots such as Hawaii. To understand better what such observations tell us about mantle flow beneath Hawaii, we have performed a direct numerical calculation of the anisotropy due to the steady flow of an ascending thermal plume interacting with a moving lithosphere. A 3-D multigrid code provides the flow field, from which the evolution of olivine lattice preferred orientation (LPO) is calculated using the plastic flow/recrystallization model of Kaminski and Ribe (Earth. Planet. Sci. Lett. 189, 253-267, 2001.) The resulting LPO field is then used to calculate the anisotropic elastic tensor Cijkl throughout the model domain. The LPO within the advected tail of the plume displays strong vertical and horizontal variations between 80 and 150 km depth, and the mean fast axis orientation e} is not sys...

ABSTRACT The Hawaiian volcanism is thought to be generated by a thermal mantle plume. A 3-D conve... more ABSTRACT The Hawaiian volcanism is thought to be generated by a thermal mantle plume. A 3-D convection code using the hybrid spectral/finite difference technique of Christensen & Harder (1991) describes the interaction of the Hawaiian plume with the moving Pacific lithosphere (Ribe & Christensen, 1994). A steady state flow field solution allows to calculate the velocity gradient field and the path of rocks. This can be used to integrate along streamlines either the finite deformation or the Lattice Preferred Orientation (LPO) of upper mantle minerals (olivine, orthopyroxene). The code D-Rex describing the deformation of a mineral aggregate by dislocation creep and dynamic recrystallization provides the necessary tool to obtain the LPO (Kaminski, Ribe & Browaeys, 2004). The equivalent elastic tensor at each position of the model is calculated using both the Orientation Distribution Function related to the LPO and tabulated elastic tensor of minerals. The tensor is then reduced to its transverse isotropic part by decomposition into different symmetry class components (Browaeys & Chevrot, 2004). The convolution of the sensitivity kernels for shear wave splitting in a transverse isotropic medium (Favier & Chevrot, 2004) with the 3-D distribution model of transverse isotropy gives variation of the splitting intensity I(alpha ) with the backazimuth alpha of the teleseismic wave. The splitting intensity can be related to the parameters of classical ray theory (time delay delta t and fast axis direction phi 0) by the relationship I(alpha )=delta t sin2 (alpha -phi 0). A comparison between the fast axis orientations in the 3-D model and the fast direction deduced from the classical expression of I(alpha ) is done. It shows that in regions where the wave propagates through inhomogeneous anisotropic properties compare to the typical wavelength of a teleseismic wave (i.e. lambda ˜ 50 km), there is no simple relation between the seismic anisotropy observations and the underlying anisotropic structure in the upper mantle.

The Ocean Island Basalts (OIB) have specific geochemical signatures (large scattering in the 3He/... more The Ocean Island Basalts (OIB) have specific geochemical signatures (large scattering in the 3He/4He ratio, large 40Ar/36Ar ratio), which suggest that they originate from several reservoirs, one of which should be undegassed. It was long assumed that the undegassed reservoir is hidden in the lower mantle (or is the lower mantle itself), but the discovery of slabs penetrating in the deep mantle invalidated this hypothesis. This apparent contradiction can however be removed assuming that the undegassed reservoir consists of domes of chemically differentiated material located in the deep mantle, as revealed by numerical experiments of thermo-chemical convection we recently conducted. These experiments showed that: (1) a strong thermal viscosity contrast create and maintain large pools of dense material at the bottom of the system; and (2) an endothermic phase transition at 660-km depth prevents the dense primitive material to massively flow into the upper part of the system. As a result, the secondary thermal plumes that are generated at the top of the pools of dense material dramatically thin at the 660 km boundary and entrain only a very small amount of dense material upwards. Reservoirs of dense primitive material (resulting, e.g., from early differentiation) can thus survive for durations comparable to the age of the Earth, and small amounts of this dense primitive material is periodically injected in the upper mantle and transported to the surface. We run additional experiments of thermo-chemical convection, in which we varied the chemical density contrast between the dense primitive and regular materials (measured by the buoyancy ratio B) and the Clapeyron slope at 660 km (Gamma660), and for each experiment, we quantified the fraction of dense primitive material that is transported by the thinned plumes and compared it to available constraints from geochemistry. We found that the mass fraction of dense material transported by secondary plumes (xPM) decreases with increasing B, and decreases with decreasing Gamma660. Taking Gamma660 = -1.0 MPa/K, which is a conservative value, xPM varies between 0.04 and 0.21 for a reasonable range of buoyancy ratio (0.25 >= B >= 0.15). Taking B = 0.2 (equivalent, in our models, to a chemical density contrast of 80 kg/m3), xPM varies between 0.17 and 0.05 for values of Gamma660 between -0.5 and -3.0 MPa/K. Assuming that the primitive reservoir's helium ratio ([3He/4He]PM) is around 12500, mass balance geochemical calculations indicate that the fraction of primitive material entrained in the secondary plumes should not exceed 0.1. Within the current uncertainties in [3He/4He]PM, the fraction of primitive material that should not be exceeded in plumes may be up to 0.2. This is larger than the fraction of primitive material entrained by secondary plumes in models with reasonable values of Gamma660 and B for the Earth's mantle. Thus, models of thermo-chemical convection that include an endothermic phase transition at 660 km, a large thermal viscosity contrast, and a moderate chemical density contrast, qualitatively and quantitatively support the hypothesis that OIB partially sample a reservoir of undegassed, dense primitive material located in the lower mantle.

From a compositional, dynamical, and structural standpoint, subduction zones are arguably Earth&a... more From a compositional, dynamical, and structural standpoint, subduction zones are arguably Earth's most complex tectonic setting. Significant uncertainty remains regarding the extent of coupling between lithospheric plates and surrounding mantle, as well as the extent to which the mantle wedge is hydrated in subduction systems. A key observation used to address these issues is measurements of seismic anisotropy, which while

Frontiers in Earth Science

In the last 70 years, geophysics has established that the Earth’s outer core is an FeNi alloy con... more In the last 70 years, geophysics has established that the Earth’s outer core is an FeNi alloy containing a few percent of light elements, whose nature and amount remain controversial. Besides the classical combinations of silicon and oxygen, hydrogen has been advocated as the only light element that could account alone for both the core density and velocity profiles. Here we show how this question can be addressed from an independent viewpoint, by exploiting the tomographic information provided by atmospheric neutrinos, weakly-interacting particles produced in the atmosphere and constantly traversing the Earth. We evaluate the potential of the upcoming generation of atmospheric neutrino detectors for such a measurement, showing that they could efficiently detect the presence of 1 wt% hydrogen in the Earth’s core in 50 years of concomitant data taking. We then identify the main requirements for a next-generation detector to perform this measurement in a few years timescale, with the ...

… 2010, held 2-7 May …, 2010

The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Sp... more The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate ...

ESA Living Planet Symposium, Dec 1, 2010

Riassunto GlobVolcano è un progetto finanziato dall'ESA (European Space Agency) nell'ambito del p... more Riassunto GlobVolcano è un progetto finanziato dall'ESA (European Space Agency) nell'ambito del programma Data User Element (DUE). Il progetto è finalizzato alla realizzazione e dimostrazione di un servizio a scala globale, basato su dati di osservazione della terra (EO Earth Observation), a supporto delle attività degli Osservatori Vulcanologici e/o Enti di Protezione Civile incaricati della sorveglianza in aree vulcaniche attive. Nel corso della prima fase del progetto il sistema informativo è stato progettato, sviluppato e validato. La validazione è stata effettuata per un numero limitato di aree test (Colima in Messico,

… 2010, held 2-7 May …, 2010

The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Sp... more The GlobVolcano project (2007-2010) is part of the Data User Element programme of the European Space Agency (ESA). The project aims at demonstrating Earth Observation (EO) based integrated services to support the Volcano Observatories and other mandate ...