C. Jaupart

Paris Institute of Earth Physics

Along the strike of subduction zones, tectonic tremor episodicity is segmented on a geologic scale. Here, we study how this segmentation reflects large‐scale variations of the structure and conditions of the fault interface where tremor is generated. We try to understand which properties of the hydraulic system of the fault allow elementary tremor...

Along the strike of subduction zones, tectonic tremor activity is segmented on a geologic scale, indicating local variations of the tremor-generating process. Here, we study how strong temporal clustering and long-term recurrence of activity can emerge from the synchronization of elementary tremor sources, as they interact through fluid pressure tr...

We propose an interactive animation method for the ejection of gas and ashes mixtures in volcano eruption. Our novel, layered solution combines a coarse-grain, physically-based simulation of the ejection dynamics with a consistent, procedural animation of multi-resolution details. We show that this layered model can be used to capture the two main...

The occurrence and the style of volcanic eruptions are largely controlled by the ways in which magma is stored and transported from the mantle to the surface through the crust. Nevertheless, our understanding of the deep roots of volcano-magmatic systems remains very limited. Here, we use the sources of seismovolcanic tremor to delineate the active...

Thick lava flows that are a feature of many volcanic fields on Earth and Venus vary from sheet-like to nearly perfect axisymmetric domes. Here, we investigate how these geometrical characteristics depend on the shape of the feeder vent. We study the gravitational spreading of viscous lava erupting from elliptical vents onto a flat surface using thr...

The bulk composition of the continental crust can be constrained from its surface heat flow. Published values of heat flow and heat production from 17 areas ranging in age from 3.3 to 0.4 Ga are compared. In the Superior province, the ca. 2.7 Ga accreted belts have a heat flow of 41mWm−2, significantly higher than that in the older, ca. 3.0 Ga, cra...

In many subduction zones, the plate interface hosts intermittent, low‐frequency, low‐magnitude seismic tremor and low‐frequency earthquakes (LFEs). Seismic activity clusters in episodic bursts that migrate along the fault zone in complex ways. Geological structures in fossil tremor source regions testify to large and pervasive variations of fluid p...

In many subduction zones, the plate interface hosts intermittent, low-frequency, low-magnitude seismic tremor and low-frequency earthquakes (LFEs). Seismic activity clusters in episodic bursts that migrate along the fault zone in complex ways. Geological structures in fossil tremor source regions testify to large and pervasive variations of fluid p...

The Earth's mantle is chemically heterogeneous and includes primordial material inherited from early planetary processes, which probably led to an initial depth-dependent composition of radioactive elements. One consequence is that its internal heat sources are not distributed homogeneously. Mantle convection induces mixing, such that the flow patt...

The activity of slow-earthquakes in subduction zones have been closely linked to fluid circulation processes — like hydro-fracturation and pore-pressure pulses — on the one hand by geological observations and on the other hand by slow-earthquake triggering and interaction models. In deep fault zone environments, where slow slip events and various r...

The exchange of volatile species—water, carbon dioxide, nitrogen and halogens—between the mantle and the surface of the Earth has been a key driver of environmental changes throughout Earth’s history. Degassing of the mantle requires partial melting and is therefore linked to mantle convection, whose regime and vigour in the Earth’s distant past re...

From nearly locked to earthquake ruptures, fault zones witness a continuous spectrum of transient, slow slip behaviors. On the shorter and smaller end of slip transients, events are detected through low-frequency earthquake activity peaks that indicate active sliding of the interface. The activation of those slow-slip transients are likely governed...

The Earth’s mantle is chemically heterogeneous and probably includes primordial material that has not been affected by melting and attendant depletion of heat-producing radioactive elements. One consequence is that mantle internal heat sources are not distributed uniformly. Convection induces mixing, such that the flow pattern, the heat source dist...

À la suite du séisme de l’Aquila, en Italie, en 2009, des sismologues italiens ont été condamnés en première instance à une peine de prison ferme, accusés de n’avoir pas su prévoir les événements. Les géophysiciens français travaillant sur les risques telluriques se sont alors interrogés sur le degré de préparation de la communauté scientifique fra...

The generation of crustal material and the formation of continental crust with a thickness of ≈40 km involve different physical mechanisms operating over different time-scales and length-scales. This review focusses on the building of a thick crustal assemblage and on the vertical dimension where the consequences of gravity-driven processes are exp...

The important scientific questions that will form the basis of a full proposal to drill a deep well to the ductile–brittle transition zone (T>400 °C) at Newberry Volcano, central Oregon state, USA, were discussed during an International Continental Drilling Program (ICDP) sponsored workshop held at the Oregon State University-Cascades campus in Ben...

Low-frequency earthquakes (LFEs) have been observed in subduction zones and some major tectonic faults and may well be the most important constituents of tectonic tremors. In subduction zones, they were initially attributed to fluids released by dehydration reactions in downgoing slabs. Their seismic radiation pattern, however, is consistent with s...

Motions in the solid mantle of silicate planets are predominantly driven by internal heat sources and occur in laminar regimes that have not been systematically investigated. Using high-resolution numerical simulations conducted in three dimensions for a large range of Rayleigh–Roberts numbers ( $5\times 10^{3}\leqslant Ra_{H}\leqslant 10^{9}$ ), w...

Convective motions in silicate planets are largely driven by internal heat sources and secular cooling. The exact amount and distribution of heat sources in the Earth are poorly constrained and the latter is likely to change with time due to mixing and to the deformation of boundaries that separate different reservoirs. To improve our understanding...

New measurements of the surface heat flux and radiogenic heat production in deep boreholes at 8 different sites are added to 10 older data to determine the heat flow field around the Sudbury basin, Ontario, Canada. This structure straddles the boundary between the Archean Superior Province to the North and the PaleoProterozoic Southern Province to...

Nevado del Ruiz volcano (NRV), Columbia, is one of the most dangerous volcanoes in the world and caused the death of 25,000 people in 1985. Using a new algorithm for repeated tomography, we have found a prominent seismic anomaly with high values of the Vp/Vs ratio at depths of 2–5 km below the surface, which is associated with a shallow magma reser...

Laboratory experiments document the post-emplacement behaviour of mafic intrusions that spread at a density interface and founder as they become denser than their surroundings due to cooling and crystallization. All else being equal, the larger the intrusion volume, the farther the intrusion can spread and the smaller its aspect ratio is. The final...

Studies of the Earth's thermal evolution have progressed slowly because of the fundamental difficulty of dealing with a highly heterogeneous system that continuously changes its upper boundary conditions and internal distribution of heat sources. Here, we review current understanding on the mechanisms of heat loss and on the partition of heat sourc...

Geochemical and petrological data indicate that the bulk continental crust results from the fractionation of basaltic magmas followed by the foundering of residual mafic cumulates. Structural and geological evidence for foundering has been elusive and it is argued that it lies in the shapes of mafic intrusions that have been preserved in the crust....

The Toba Caldera has been the site of several large explosive eruptions in the recent geological past, including the world's largest Pleistocene eruption 74,000 years ago. The major cause of this particular behaviour may be the subduction of the fluid-rich Investigator Fracture Zone directly beneath the continental crust of Sumatra and possible tea...

Supplementary Figures 1-8 and Supplementary Tables 1-2

The thermal structure and evolution of continents depend strongly on the amount and distribution of radioactive heat sources in the crust. Determining the contribution of crustal rocks beneath a superficial layer is a major challenge because heat production depends weakly on major element composition and physical properties such as seismic wavespee...

We review both the constraints and the models pertaining to the global energy budget of the mantle.

The post-orogenic thermal evolution of newborn cratons in the Archean is marked by high-temperature metamorphism and plutonic activity that lag accretion by several tens of million years. The source of the heat that is required remains controversial. Here, we show that such late activity is consistent with the thermal evolution of new continental c...

The thermal evolution of telluric planets is primarily controlled by the balance between internal heating - due to radioactive decay - and efficiency of convective heat transfer in their mantle. In the Earth, the problem is particularly complex due to the heterogeneous distribution of heat sources in the mantle and the non-linear coupling between t...

Thermal evolution of telluric planets is mainly controlled by secular cooling and internal heating due to the decay of radioactive isotopes, two processes that are equivalent from the standpoint of convection dynamics. In a fluid cooled from above and volumetrically heated, convection is dominated by instabilities of the top boundary layer and the...

Heat provides the energy that drives almost all geological phenomena and sets the temperature at which these phenomena operate. This book explains the key physical principles of heat transport with simple physical arguments and scaling laws that allow quantitative evaluation of heat flux and cooling conditions in a variety of geological settings an...

In a volcanic area, the orientation and composition of dikes record the development of the magmatic system that feeds intrusive and eruptive activity. At Spanish Peaks, Colorado, curved dike trajectories issuing from a single focal area have been attributed to horizontal propagation from a pressurized central reservoir in a deviatoric tectonic stre...

How continental lithosphere responds to tectonic stresses and mantle convective processes is determined in large part by its mechanical strength and temperature distribution, which depend on crustal heat production. In order to establish reliable crustal and thermal models for the Superior craton, Canadian Shield, new measurements of heat flux and...

We review models and data on heat flux and the temperature regime and discuss the geological/geophysical parameters that control the thermal structure of the lithosphere. The thickness of the thermal lithosphere is defined as the depth where the conductive geotherm intersects the mantle isentrope. We discuss the cooling plate model for the oceanic...

Heat flow and heat production data complement seismic information and provide strong constraints on crustal composition, thickness and evolution. They have helped understand the nature of the Mohorovicic discontinuity and the variations in seismic velocities below the Moho. Notably, heat flow studies have delineated the vertical distribution of hea...

The thermal evolution of terrestrial planets is mainly controlled by the amount of radioactive heat sources in their mantle, and by the geometry and efficiency of solid state thermo-chemical convection within. So far, these systems have been studied using numerical methods only and cross validation by laboratory analogous experiments has not been c...

[1] Continents may be affected simultaneously by rifting, uplift, volcanic activity, and basin formation in several different locations, suggesting a common driving mechanism that is intrinsic to continents. We describe a new type of convective instability at the base of the lithosphere that leads to a remarkable spatial pattern at the scale of an...

The long geological history of passive margin evolution is complex yet typified by an initial ramp-like tilting of the subaerial surface towards the continent-ocean boundary, followed by episodic uplift and subsidence at a smaller wavelength. We argue that this behaviour is due to changes in margin structure brought about by buoyancy-driven lithosp...

Intracratonic basins are enigmatic, large, and very long-lived sedimentary basins that exits across all the continental landmasses. After formation the subsidence history continues for hundreds of millions of years, providing a potential archive of change in climate and mantle dynamics. Subsidence within these basins initiates during periods of bre...

The Cameroon Volcanic Line (CVL) is an enigmatic structure that defies common dynamic models of melt generation and volcanic activity on Earth. There, magma generation and intrusion has been sustained for more than 70 Myr over a 1600 km long chain straddling the ocean–continent boundary, with no detectable spatial age progression. The chain is near...

We propose the liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) as a next-generation neutrino observatory on the scale of 50 kt. The outstanding successes of the Borexino and KamLAND experiments demonstrate the large potential of liquid-scintillator detectors in low-energy neutrino physics. LENA's physics objectives comprise the ob...

Striking observations have been made that challenge our understanding of magma migration through the Earth's crust. How may a volatile rich magma stall at shallow depth as a growing crypto-dome such as during the 1980 Mount Saint Helens eruption? How can we explain the width of the 2005 mega-dyke intrusion in Afar, that attained more than 8 meters...

The total energy loss of the Earth is well constrained by heat flux measurements on land, the plate cooling model for the oceans, and the buoyancy flux of hotspots. It amounts to 46±2TW. The main sources that balance the total energy loss are the radioactivity of the Earth's crust and mantle, the secular cooling of the Earth's mantle, and the energ...

We investigate how subduction may be triggered by continental crust extension at a continental margin. The large topography contrast between continental and oceanic domains drives the spreading of continental crust over oceanic basement. Subduction requires the oceanic plate to get submerged in mantle, so that negative buoyancy forces may take over...

Continental lithosphere is far thicker than its oceanic counterpart. The boundary between continent and ocean marks a transition in lithospheric thermal and chemical properties. This change in lithosphere structure can potentially nucleate downward travelling Rayleigh-Taylor instabilities that have the potential to generate melt, influence margin t...

The total energy loss of the Earth is well constrained by heat flux measurements on land, the plate cooling model for the oceans, and the buoyancy flux of hotspots. It amounts to 46±2 TW. The main sources that balance the total energy loss are the radio-activity of the Earth's crust and mantle, the secular cooling of the Earth's mantle, and the ene...

Geo-neutrino observations are presently underway in several underground neutrino observatories and the development of new observatories is being planned. Such observations will provide direct constraints on the abundance of U and Th in the crust and mantle and on their contribution to the Earth's energy budget. The geo-neutrino flux in continental...

Many extension zones have been subjected to folding and shortening in a direction perpendicular to the stretching. Such deformation can be accounted for by the extension of a thin superficial elastic layer overlying a substrate that has small elastic moduli or that deforms in a viscous regime. Laboratory experiments are used to document the wavelen...

Magma ascent towards the Earth’s surface occurs through dyke propagation in the vast majority of cases. We investigate two purely mechanical effects unrelated to cooling or solidification that lead to the arrest of propagation, so that no eruption occurs. The first is that the input of magma from the source is not maintained continuously, such that...

It is now clear that magma reservoirs develop over long time intervals out of a large number of individual intrusions. Evidence from some large volcanic deposits, including those of the Bishop Tuff, California, and Fish Canyon Tuff, Colorado, indicates that such reservoirs may experience pervasive and rapid heating before catastrophic eruptions. In...

Heat flow studies on the exposed part of the Trans-Hudson Orogen (THO) in northern Manitoba and Saskatchewan allow constraints on crustal composition and lithosphere structure. The average of all heat flow values in the THO is the same as in other geological provinces of the Canadian Shield. However, where juvenile crust is exposed, heat flow is on...

New heat flow density (HFD) measurements were performed at 10 sites in Quebec. For five of the sites located in the Superior Province, the heat flow density varies between 24 and 35 mW/m2 (26 and 37 mW/m2 after adjustment for Pleistocene climatic variations). In the Grenville Province, the values obtained range between 25 and 28 mW/m2 (29 and 31 mW...

We combine heat flux data and seismic velocity models for the North American lithosphere to derive constraints on thermal conditions and deformation mechanisms in the underlying convecting mantle. Local heat flux averages that are not affected by shallow crustal heat production contrasts allow calculation of reliable lithospheric geotherms and unce...

The influence of magma expansion due to volatile exsolution and gas dilation on dyke propagation is studied using a new numerical code. Many natural magmas contain sufficient amounts of volatiles for fragmentation to occur well below Earth's surface. Magma fragmentation has been studied for volcanic flows through open conduits but it should also oc...

The Earth loses energy as heat flows out through its surface. The total energy loss of the Earth has been estimated at 46 ± 2 TW, of which 14 TW comes through the continents and 32 TW comes from the seafloor. After removing the heat production of radioactive elements in the continental lithosphere, the energy loss from the convecting mantle is 39 T...

Editor: Y. Ricard Keywords: basaltic eruptions volcanic plumes penetrative convection continental flood basalts global environment Turbulent volcanic plumes disperse fine ash particles and toxic gases in the atmosphere and can lead to significant temperature drops in the atmosphere. In the geological past, the emplacement of large continental flood...

The influence of magma expansion due to volatile exsolution and gas dilation on dike propagation is studied using a new numerical code. Many natural magmas contain sufficient amounts of volatiles for fragmentation to occur well below Earth's surface. Magma fragmentation has been studied for volcanic flows through open conduits but it should also oc...

We use new and published heat flux determinations and shear wave travel time delays to infer the deep thermal structure of the lithosphere in eastern North America, beneath geological provinces that range in age from Archean (>2.5Ga) to Paleozoic (

Thick depleted continental lithosphere may act as a buffer region where stresses imparted by mantle convection get attenuated. Yet, it may generate its own convective motions because it is cooled from above and hence potentially unstable. One should evaluate carefully the consequences of lithosphere destabilization before attributing systematically...

The behaviour of a magma plumbing system during a cycle of volcanic edifice growth is investigated with a simple physical model. Loading by an edifice at Earth's surface changes stresses in the upper crust and pressures in a magma reservoir. In turn, these changes affect magma ascent from a deep source to the reservoir and from reservoir to Earth's...

The effects of horizontal heat conduction due to radioactivity variations are investigated within the framework of the linear relation discovered by Birch and colleagues: Qo=Qr+ D. Ao. We study the relationship between the apparent depth-scale which is deduced from this relation and the true depth-scale for uniform and exponential vertical distribu...

Ten new heat flux determinations have been made using measurements in 22 mining exploration boreholes located at latitudes higher than 51°N in the Canadian Shield. They provide data in poorly sampled regions near the core of the North American craton where one expects the lithosphere to be thickest. The new heat flux values are all smaller than 34...

We propose a new model of Earth's bulk composition based on enstatite chondrites (E-chondrites), the only chondrite group isotopically identical to the Earth. This model allows a quantitative study of accretion and differentiation processes in the early Earth. Conditions for core formation are evaluated using data on silica–iron equilibrium at high...

Geothermal studies were conducted within the framework of Lithoprobe to systematically document variations of heat flow and surface heat production in the major geological provinces of the Canadian Shield. One of the main conclusions is that in the Shield the variations in surface heat flow are dominated by the crustal heat generation. Horizontal v...

Heat provides the energy that drives almost all geological phenomena and sets the temperature at which these phenomena operate. This book explains the key physical principles of heat transport with simple physical arguments and scaling laws that allow quantitative evaluation of heat flux and cooling conditions in a variety of geological settings an...

The Hudson Bay region has experienced subsidence and perhaps extension in the Paleozoic and yet seems to be associated with anomalously thick lithosphere according to global and regional seismic tomography models. Changes of thermal structure and/or lithospheric thickness at the base of a deep continental root (~300 km) lead to large-scale surface...

The mechanisms controlling continental rifting, break-up and subsequent subsidence are strongly influenced by the thermal regime of the lithosphere. We present marine heat flow measurements from the Eastern Gulf of Aden, which is a recently formed divergent margin between Africa and Arabia, as well as terrestrial measurements in the Arabian platfor...

Although continental interiors are commonly described as stable, many have been subjected to major perturbations. The North American continent, for example, saw the formation or reactivation of four intracratonic basins (Williston, Hudson Bay, Illinois and Michigan) in the Paleozoic about 500 million years ago. These events occurred far from ocean...

Magma reservoirs probably grow incrementally by repeated sill-like intrusions. We investigate the conditions for repeated intrusions at the same crustal level by a feeder dike before a permanent molten reservoir can form. Sill inception requires that magma within a dike develops an overpressure that is large enough to overcome the strength of surro...

Many natural magmas contain sufficient amounts of volatiles for fragmentation below Earth's surface. Magma fragmentation has usually been studied for volcanic flows through open conduits that feed eruptive vents but it should also occur within a dike that rises towards Earth's surface. We have used a new numerical code to investigate how dike propa...

We have used RADARSAT SLC images from the Canadian Space Agency to create complex interferograms from part of the northern volcanic zone in Iceland. The dataset covers the 2000-2009 period and is a valuable addition to the limited number of good interferometric image pairs available for the area during this time, due to problems with the ERS in 200...

The geo-neutrino flux at the Sudbury Neutrino Observatory depends on the local level of crustal radio-activity, which is best estimated from surface heat flux data. The surface heat flux records average crustal radio-activity over the whole crustal column and is unaffected by small-scale heterogeneities. We show how the contribution of crustal heat...

Dike penetration through a succession of upper crustal layers with different densities is studied with a new numerical code. For an individual layer to significantly affect dike ascent, its thickness must be of order 1 when scaled to the characteristic length-scale for the inflated nose region that develops below the dike tip. This characteristic l...

Available heat flux data cover the Southern part of the Canadian Shield and extend northward to the regions east and west of James Bay. The northernmost data are located near the core of the North American craton where one expects the lithosphere to be thickest. All the heat flux values in the James Bay area are less than 34 mW~m-2 and are amongst...

During its next phase, the Sudbury neutrino observatory (SNO) will detect geoneutrinos, antineutrinos produced by the decay of U and Th in the Earth. These observations will provide direct constraints on the contribution of radiogenic heat production in the crust and mantle to the energy budget of the Earth. The geoneutrino flux at SNO depends on t...

Determination of the rate of Earth's energy loss is based a very large number of heat flux measurements in a variety of geological settings. Difficulties in integrating the flux over the Earth surface stem from two facts. One is that heat flux varies on a wide range of spatial scales and, in continents, is not a function of a single variable such a...