Eric Calais

• PhD
• Professor (Full) at Ecole Normale Supérieure de Paris

The Caribbean plate and its boundaries with north and south America, marked by subduction and large intra-arc strike-slip faults, are a natural laboratory for the study of strain partitioning and interseismic plate coupling in relation to large earthquakes. Here we use most of the available campaign and continuous GPS measurements in the Caribbean...

Although many continental rifts and passive margins are magmatic, some are not1. This dichotomy prompted end-member views of the mechanisms driving continental rifting, deep-seated and mantle plume-driven for some2, owing to shallow lithospheric stretching by far-field forces for others3. In that regard, the Central East African Rift (CEAR) provide...

Present-day continental extension along the East African Rift System (EARS) has often been attributed to diverging sub-lithospheric mantle-flow associated with the African Superplume. This implies a degree of viscous coupling between mantle and lithosphere that remains poorly constrained. Recent advances in estimating present-day opening rates alon...

The East African Rift (EAR) is a type-locale for investigating the processes that drive continental rifting and breakup. The current kinematics of this ~5000-km long divergent plate boundary between the Nubia and Somalia plates is starting to be unraveled thanks to a recent augmentation of space geodetic data in Africa. Here, we use a new data set...

The spatiotemporal behaviour of earthquakes within continental plate interiors is different from that at plate boundaries. At plate margins, tectonic motions quickly reload earthquake ruptures, making the location of recent earthquakes and the average time between them consistent with the faults' geological, palaeoseismic and seismic histories. In...

The 14 August 2021 Haiti earthquake mainly portrayed reverse motion to the east near L’Asile town and left‐lateral strike‐slip motion to the west near Camp‐Perrin town. To map the rupture and infer its segmentation, we conducted the first post‐seismic field reconnaissance along the left‐lateral strike‐slip Enriquillo fault from L’Asile to Macaya mo...

Cet article revient sur l’histoire d’Haïti pour présenter la construction de la notion de citoyenneté dans le pays et démontrer que, aujourd’hui, cette dernière n’est pas pleinement réalisée tant la coupure entre la population et l’État – parfois qualifié de « failli » – est forte. Elle est même instrumentalisée par les gangs qui disent représenter...

Seismic hazard levels used as reference for the French Lesser Antilles are derived from probabilistic seismic hazard assessment studies performed in 2002. However, scientific knowledge has greatly increased over the past 20 years in this area, warranting an update of the seismic hazard models. As part of a project linking the French Ministry of Eco...

Global Navigation Satellite System (GNSS) measurements at episodic sites or continuously operating stations have been used in most actively deforming regions to determine strain rates, fault slip rates, and contribute to assessing regional seismic hazard. However, the central part of the northern Caribbean plate boundary in Cuba has so far been exe...

This paper presents the first application of multichannel singular spectrum analysis (M-SSA) to radar satellite geodesy. We apply M-SSA to Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) time series processed for Pacaya Volcano in Guatemala in two steps. First, we produce, in an iterative and data-adaptive way, estimates of missing data...

Seismic monitoring in Haiti is currently provided by a mixed network of low-cost Raspberry Shake (RS) seismic stations hosted by citizens, and short-period and broadband stations located mainly in neighboring countries. The level of earthquake detection is constantly improving for a better spatio-temporal distribution of seismicity as the number of...

On 14 August 2021 the Mw 7.2 Nippes earthquake struck southern Haiti, rupturing a segment of the Enriquillo‐Plantain Garden Fault system (EPGF), a 300 km‐long strike‐slip fault system that accommodates half of the highly oblique convergence displacement between the Caribbean and the North American plates. We use coseismic surface displacements from...

GNSS measurements at episodic sites or at continuously operating stations have been used in most actively deforming regions to determine strain rates and fault slip rates. They are also useful for gaining insights on the underlying seismotectonic processes, the mechanical behavior of faults, or more generally the regional seismic hazard. GNSS measu...

On January 12, 2010, Haiti was hit by one of the largest seismic disasters known to date. At the time, the culture and perception of seismic risk was low among the population and—because of the lack of seismic sensors in Haiti—so was seismological knowledge. In a citizen seismology approach, the S2RHAI project used low-cost seismic sensors (Raspber...

Global Positioning System measurements and high-resolution offshore seismic data within the transform Caribbean–North American plate boundary in southern Haiti, Greater Antilles, show 6–7 mm/yr of plate boundary-normal shortening within a crustal sliver bounded to the south by the Enriquillo left-lateral strike-slip fault and to the north by a sout...

The 14 August 2021 Mw 7.2 Haiti earthquake struck 11 yr after the devastating 2010 event within the Enriquillo Plantain Garden (EPG) fault zone in the Southern peninsula of Haiti. Space geodetic results show that the rupture is composed of both left-lateral strike-slip and thrust motion, similar to the 2010 rupture; but aftershock locations from a...

On January 12, 2010, Haiti was hit by one of the largest seismic disasters known to date. This disaster is part of a long series of crises that affect Haitians, whether natural (hurricanes, earthquakes...) or related to political and economic factors (demonstrations, impoverishment...). Using a citizen seismology approach, a multidisciplinary team...

In continental interiors, tectonically-driven deformation rates are low, often to the point where they are undetectable with modern geodesy. However, a range of non-tectonic surface processes, particularly relating to hydrological, cryospheric, and sedimentological mass changes, can produce strain-rates which on geologically-short timescales are su...

Space geodetic time series, be they ground-based or space-based, have increased in length and accuracy. These series can now be mined for information on the qualitative dynamics of volcanic systems directly from surface deformation data. Here, we study three volcanoes: Akutan and Okmok that are part of the Aleutian arc, and Piton de la Fournaise on...

Geological estimates of vertical motions in the central part of the Lesser Antilles show subsidence on timescales ranging from 125.000 to 100 years, which has been interpreted to be caused by interseismic locking along the subduction megathrust. However, horizontal GNSS velocities show that the Lesser Antilles subduction interface is currently buil...

Recent installation of GPS (Global Positioning System) network in northern Algeria (the REGAT REseau Geodesique de l’ATlas Project), combined with the seismic ADSN (Algerian Digital Seismic Network) data network, fills an important gap in our knowledge of the present-day Nubian–Eurasian plate boundary in the western Mediterranean where likely most...

The August 14, Mw7.2, Nippes earthquake in Haiti occurred within the same fault zone as its devastating, Mw7.0, 2010 predecessor but struck the country when field access was limited by insecurity and conventional seismometers from the national network were inoperative. A network of citizen seismometers installed in 2019 provided near-field data cri...

In the current plate tectonics paradigm, relative plate motions are assumed to remain unperturbed by temporal stress changes occurring during the seismic cycle, whereby stress slowly built up along tectonic plate boundaries is suddenly released by rapid fault slip during earthquakes. However, direct observations that could challenge such a tenet ha...

The macroseismic and instrumental observations accumulated by the Bureau Central Sismologique Français and other national agencies over the last 100 years show that the northwestern part of metropolitan France is affected by an apparently diffuse and moderate intraplate seismicity. Far from any plate boundary, well-documented inherited structures,...

Geological estimates of vertical motions in the central part of the Lesser Antilles show subsidence on timescales ranging from 125.000 to 100 years, which has been interpreted to be caused by interseismic locking along the subduction megathrust. However, horizontal GNSS velocities show that the Lesser Antilles subduction interface is currently buil...

The Lesser Antilles subduction zone is a challenging region when it comes to unraveling its seismogenic behavior. Over the last century, the subduction megathrust has been seismically quiet, with no large thrust event recorded, which raises the question whether this subduction zone is able to produce large interplate earthquakes or not. However, tw...

Earthquake risk reduction approaches classically apply a top-down model where scientific information is processed to deliver risk mitigation measures and policies understandable by all, while shielding end-users from the initial, possibly complex, information. Alternative community-based models exist but are rarely applied at a large scale and rely...

The Lesser Antilles subduction zone is a challenging region when it comes to unraveling its seismogenic behavior. Over the last century, the subduction megathrust has been seismically quiet, with no large thrust event recorded, which raises the question whether this subduction zone is able to produce large interplate earthquakes or not. However, tw...

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...

Abstract. The devastating M_w 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...

Earthquakes in Stable Continental Regions (SCR), where localized present‐day tectonic loading is negligible, remain difficult to explain. The New Madrid Seismic Zone (NMSZ) is a type‐locale for such events, with four M>7 events in 1811–1812 and a regional seismicity that continues to this day. Here, we seek to determine the most favorable condition...

Measurements of the spatio-temporal variations of Earth’s gravity field from the Gravity Recovery and Climate Experiment (GRACE) mission have led to new insights into large spatial mass redistribution at secular, seasonal and subseasonal timescales. GRACE solutions from various processing centres, while adopting different processing strategies, res...

A network of “personal seismometers” is intended to complement Haiti’s national seismic network to engage and inform residents about earthquake hazards and preparation.

The REGAT (“REseau Géodésique de l'ATlas”) geodetic network is composed of 53 continuously–recording GPS stations distributed in the Algerian Atlas. It spans the whole width of the Algerian coast and reaches 300 km inland, with inter-sites distance of about 100 km. One additional site is located in Tamanrasset in the southernmost part of the countr...

S U M M A R Y The present-day kinematics of plate boundary deformation in the western Mediterranean is now well described by space geodetic measurements, except for the Algeria-Tunisia part of north Africa where information is still lacking. Yet, that portion of the Nubia-Eurasia Plate boundary likely concentrates most of the oblique plate converge...

Oblique convergence of the Caribbean and North American plates has partitioned strain across a major transpressional fault system that bisects the island of Hispaniola. The devastating MW 7.0, 2010 earthquake that struck southern Haiti, rupturing an unknown fault, highlighted our limited understanding of regional fault segmentation and its link to...

Complex networks of high-tech sensors are tough to operate and maintain in developing countries – but new low-costs, low-maintenance instruments may help. Because they are “connected objects” they also provide new opportunities to engage the civil society in citizen-science. Here we describe a seismological instrumentation experiment in Haiti with...

Complex networks of high-tech sensors are tough to operate and maintain in developing countries – but new low-costs, low-maintenance instruments may help. Because they are “connected objects” they also provide new opportunities to engage the civil society in citizen-science. Here we describe a seismological instrumentation experiment in Haiti with...

The time-dependent deformation of volcanic edifices can help one understand the dynamics of pre-eruptive overpressure build-up in magma chambers. Thus, geodetic time series recorded at the Okmok volcano, in Alaska, show a pattern of fast and short inflations-referred to as "pulses"-followed by either slower and longer deflations, or time intervals...

Divergent ridge-ridge-ridge (R-R-R) triple junctions are one of the most remarkable, yet largely enigmatic, features of plate tectonics. The juncture of the Arabian, Nubian, and Somalian plates is a type-example of the early development stage of a triple junction where three active rifts meet at a ‘triple point’ in Central Afar. This structure may...

Large earthquakes in stable continental regions remain puzzling as; unlike at plate boundaries, they do not result from the local buildup of strain driven by plate tectonics. The 2017 Mw6.5, Bostwana normal faulting earthquake occurred in a region devoid from recent tectonic activity and where present-day deformation is negligible. The depth of the...

Narrow and wide rifts are end‐member expressions of continental extension. Within the framework of passive rifting, the transition from wide to narrow rifts requires lowering the geothermal gradient. Reconciling this view with observational evidence for narrow rift zones in regions underlain by sub‐lithospheric hot plume material, such as the easte...

We model surface displacements induced by variations in continental water, atmospheric pressure, and non-tidal oceanic loading, derived from the Gravity and Recovery Climate Experiment (GRACE) for spherical harmonic degrees two and higher. As they are not observable by GRACE, we use at first the degree-1 spherical harmonic coefficients from (?swens...

We discuss the constraints on short-term asthenospheric viscosity provided by seasonal deformation of the Earth. We use data from 195 globally distributed continuous Global Navigation Satellite System stations. Surface loading is derived from the Gravity Recovery and Climate Experiment and used as an input to predict geodetic displacements. We comp...

The degree to which short-term non-tectonic processes, either natural and anthropogenic, influence the occurrence of earthquakes in active tectonic settings or 'stable' plate interiors, remains a subject of debate. Recent work in plate-boundary regions demonstrates the capacity for long-wavelength changes in continental water storage to produce obs...

Using numerical thermo-mechanical experiments we analyze the role of an active mantle plume and pre-existing lithospheric-thickness differences in the structural development of the central and southern East African Rift system. The plume–lithosphere-interaction model setup captures the essential features of the studied area: two cratonic bodies emb...

The devastating 2010 Mw 7.0 Haiti earthquake demonstrated the need to improve mitigation and preparedness for future seismic events in the region. Previous studies have shown that the earthquake did not occur on the Enriquillo Fault, the main plate boundary fault running through the heavily populated Port-au-Prince region, but on the nearby and pre...

We use numerical thermo-mechanical experiments in order to analyze the role of active mantle plume, far-field tectonic stresses and pre-existing lithospheric heterogeneities in structural development of the East African Rift system (EARS). It is commonly assumed that the Cenozoic rifts have avoided the cratons and follow the mobile belts which serv...

S U M M A R Y We use recently published, high-resolution reconstructions of the Southwest Indian Ridge to test whether a previously described systematic difference between Global Positioning System (GPS) and 3.16-Myr-average estimates of seafloor spreading rates between Antarctica and Africa is evidence for a recent slowdown in Southwest Indian Rid...

Kinematics of divergent boundaries and Rift-Rift-Rift junctions are classically studied using long-term geodetic observations. Since significant magma-related displacements are expected, short-term deformation provides important constraints on the crustal mechanisms involved both in active rifting and in transfer of extensional deformation between...

Triggering studies provide an important tool for understanding the fundamental physics of how faults slip and interact, and they also provide clues about the stress states of faults. In this study, we explore how seismic waves from the 27 February 2010 Mw8.8 Maule, Chile mainshock interact with the left lateral strike-slip Enriquillo–Plantain Garde...

Large earthquakes within stable continental regions (SCR) show that significant amounts of elastic strain can be released on geological structures far from plate boundary faults, where the vast majority of the Earth's seismic activity takes place. SCR earthquakes show spatial and temporal patterns that differ from those at plate boundaries and occu...

The occurrence of large earthquakes in stable continental interiors challenges the applicability of the classical steady-state ‘seismic cycle’ model to such regions. Here, we shed new light onto this issue using as a case study the cluster of large reverse faulting earthquakes that occurred in Fennoscandia at 11-9 ka, triggered by the removal of th...

The East African Rift system (EARS) provides a unique system with juxtaposition of two contrasting yet simultaneously formed rift branches, the eastern, magma-rich, and the western, magma-poor, on either side of the old thick Tanzanian craton embedded into younger lithosphere. Here we take advantage of the improvements in our understanding of deep...

The recent development of dense and continuously operating Global Navigation Satellite System (GNSS) networks worldwide has led to a significant increase in geodetic data sets that sometimes capture transient-deformation signals. It is challenging, however, to extract such transients of geophysical origin from the background noise inherent to GNSS...

The Red Sea arm of the triple junction in northeastern Ethiopia provides an opportunity to investigate rift-forming processes at divergent boundaries. In an attempt to study the subsurface, especially the distribution and role of melt in the rifting process, we carried out a high-precision gravity survey with a mean-square error of 0.011 mgal, assi...

The Caribbean–North America plate boundary in the northeastern Caribbean shows a remarkable example of along-strike transition from plate boundary–normal subduction in the Lesser Antilles, oblique subduction with no strain partitioning in Puerto Rico, and oblique subduction/collision with strain partitioning further west in Hispaniola. We show that...

The East African Rift system (EARS) provides a unique system with the juxtaposition of two contrasting yet simultaneously formed rift branches, the eastern, magma-rich, and the western, magma-poor, on either sides of the old thick Tanzanian craton embedded in a younger lithosphere. Data on the pre-rift, syn-rift and post-rift far-field volcanic and...

The northeastern Caribbean island arc, which materializes the boundary between the North American and Caribbean plates, is particularly exposed to large earthquakes and tsunamis. The low level of preparedness of a large part of its population and the lack of risk reduction provisions in public policies in many countries of the region put their popu...

The Mw 7 earthquake of January 12, 2010, in Haïti was followed by a tsunami with wave heights reaching 3n m in some locations (Grand Goâve, Jacmel) on either side of the Presqu’Ile du Sud where the event took place. The tsunami was also recorded at DART buoy 42407 (about 600 km southeast of the earthquake source) and at a tide gauge in Santo Doming...

Earthquake activity in parts of the central United States has increased dramatically in recent years. The space-time distribution of the increased seismicity, as well as numerous published case studies, indicates that the increase is of anthropogenic origin, principally driven by injection of wastewater coproduced with oil and gas from tight format...

It is debated to what extent mantle plumes play a role in continental rifting and eventual break-up. Afar lies at the northern end of the largest and most active present-day continental rift, where the East African Rift forms a triple junction with the Red Sea and Gulf of Aden rifts. It has a history of plume activity yet recent studies have reache...

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...

Extension, faulting and magmatism are the main controls on the magnitude and localization of strain at mid-ocean ridges. However, the temporal and spatial patterns of such processes are not clear since the strain distribution has not been resolved in the past at sufficient spatial resolution and over extended areas. InSAR and GPS data with unpreced...

The contemporary horizontal movements and deformations in the central and southern parts of the Baikal depression are analyzed, and their relationship with contemporary seismicity is studied. Based on the long-term measurements by the Baikal geodynamical GPS monitoring network, the refined estimate is obtained for the velocity of the divergence of...

Extension, faulting, and magmatism are the main controls on the magnitude and localization of strain at mid-ocean ridges. However, the temporal and spatial patterns of such processes are not clear since the strain distribution has not been resolved in the past at sufficient spatial resolution and over extended areas. Interferometric synthetic apert...

The mechanical behavior – and hence earthquake potential – of faults in continental interiors is an issue of critical importance for the resultant seismic hazard, but no consensus has yet been reached on this controversial topic. The debate has focused on the central and eastern United States, in particular the New Madrid Seismic Zone, struck by fo...

Although the East African Rift System (EARS) is an archetype continental rift, the forces driving its evolution remain debated. Some contend buoyancy forces arising from gravitational potential energy (GPE) gradients within the lithosphere drive rifting. Others argue for a major role of the diverging mantle flow associated with the African Superplu...

We explore the evolution of plume-activated rifting in a heterogeneous continental lithosphere containing embedded cratonic blocks, with a particular focus on the impact of horizontal position of a plume with respect to the craton. We also study the influence of a preexisting far-field stress/strain field on the «active» rifting style by implementi...

Increased displacement rates have been observed following manylarge earthquakes and magmatic events. Although an order of magnitude smaller than the displacements associate with the main event, the post-seismic or post-rifting deformation may continue for years to decades after the initial earthquake or dyke intrusion. Due to the rare occurrence of...