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Last name: MOTHES
First name: Patricia
International audience
We analyze continuous GPS measurements along the central Ecuador subduction segment to quantify three years of postseismic deformation that followed the Mw 7.8 April 16 2016 Pedernales earthquake. We perform a kinematic inversion solving for the daily slip along the subduction interface to retrieve the afterslip evolution through space and...
In subduction zones, slip along the plate interface occurs in various modes including earthquakes, steady slip, and transient accelerated aseismic slip during either Slow Slip Events (SSE) or afterslip. We analyze continuous GPS measurements along the central Ecuador subduction segment to illuminate how the different slip modes are organized in...
The North Andean Sliver (hereinafter NAS) lies at the northwestern end of the South American plate (hereinafter SOAM). This extensive area exhibits a complex deformation process controlled by the interactions of Nazca, Caribbean, South America plates, and Panama block, producing crustal seismicity, arc-continental collision, and subduction...
Cotopaxi is a large, ice-capped stratovolcano located in the Ecuadorian Andes. After 72 years of repose, Cotopaxi erupted on August 14, 2015. The precursory activity included long-period (LP) events followed by volcano-tectonic (VT) earthquakes, very-long-period events accompanying LP signals (VLP/LP events), tremor, deformation and SO2...
Cotopaxi volcano started a period of volcanic unrest in April 2015 that led to a series of eruptions between August and November 2015. We use COSMO‐SkyMed Interferometric Synthetic Aperture Radar supported by continuous GPS observations spanning the period of 2014–2016 to obtain time‐dependent ground deformation data over Cotopaxi volcano...
International audience
International audience
The continuous Global Positioning System (cGPS) network operating in the northern Andes (Ecuador and Colombia) for about a decade has the main objectives of quantifying interseismic coupling along the subduction interface, detecting occurrence of transient aseismic episodic slip, detailing the rupture kinematics of large earthquakes, recording...
At subduction zones, transient aseismic slip occurs either as afterslip following a large earthquake or as episodic slow slip events during the interseismic period. Afterslip and slow slip events are usually considered as distinct processes occurring on separate fault areas governed by different frictional properties. Continuous GPS (Global...
The volcanism of the Northern Andes is characterized by an intense Plio-Quaternary activity, whose onshore deposits have covered older products associated with the early development of the arc. To improve our knowledge of the largest explosive eruptions that occurred in the Northern Andean arc since the Miocene, we analyzed tephra layers...
The volcanism of the Northern Andes is characterized by an intense Plio-Quaternary activity, whose onshore deposits have covered older products associated with the early development of the arc. To improve our knowledge of the largest explosive eruptions that occurred in the Northern Andean arc since the Miocene, we analyzed tephra layers...
High-Rate (HR) GPS time series following the 2016 Mw 7.8 Pedernales earthquake suggest significant postseismic deformation occurring in the early postseismic period (i.e. first few hours after the earthquake) that is not resolved with daily GPS time series. To understand the characteristics of early postseismic deformation, and its relationship...
The Quito Fault System (QFS) extends over 60km along the Interandean Depression in northern Ecuador. Multidisciplinary studies support an interpretation in which two major contemporaneous fault systems affect Quaternary volcanoclastic deposits. Hanging paleovalleys and disruption of drainage networks attest to ongoing crustal deformation and...
L'identification de la source volcanique de niveaux de cendres (téphras) préservés dans les sédiments marins apporte des informations essentielles pour étudier l'impact des éruptions majeures passées et pour contraindre temporellement les séquences sédimentaires. Les sources volcaniques sont généralement déduites de corrélations terre-mer...
Identifying the sources of distal tephra in marine sediments or polar ice provides clues on the dynamic and large-scale impact of major volcanic eruptions. However, determination of the volcanic source of distal tephra is challenging due to size-dependent fractionation during atmospheric transport that modifies the mineral, chemical and even...
We document a 1 week long slow slip event (SSE) with an equivalent moment magnitude of 6.0-6.3 which occurred in August 2010 below La Plata Island (Ecuador), south of the rupture area of the 1906 Mw= 8.8 megathrust earthquake. GPS data reveal that the SSE occurred at a depth of about 10 km, within the downdip part of a shallow (<15 km),...
The 2019/05/26 Northern Peru earthquake (Mw = 8) is a major intermediate-depth earthquake that occurred close to the eastern edge of the Nazca slab flat area. We analyze its rupture process using high-frequency back-projection and seismo-geodetic broadband inversion. The latter approach shows that the earthquake propagated with almost purely...
Correlations between marine distal ash layers and continental proximal volcanic deposits constitute a strong tool to investigate the eruptive chronology of an active volcanic arc, to constrain the detailed stratigraphy of the marine sediments, as well as help constraining the magnitude of some large explosive eruptions.In the Andean Northern...
The Mw7.8 Pedernales earthquake is associated with the subduction of the Nazca Plate beneath the South American Plate. The mainshock caused many casualties and widespread damages across the Manabi province. The 150 km-long coseismic rupture area is found beneath the coastline, near 25 km depth. The rupture propagated southward and involved the...
Tephra layers preserved in marine sediments are strong tools to study the frequency, magnitude and source of past major explosive eruptions. Thirty-seven volcanoes from the Ecuadorian and Colombian arc, in the northern Andes, experienced at least one eruption during the Holocene. The volcanic hazard is therefore particularly high for the...
Along active margins, large magnitude earthquakes induce submarine slope instabilities, generating turbidite deposits and debris flows. These catastrophic events are recorded in the stratigraphy from the slope basins to the subduction trench. These sedimentary records provide a unique opportunity to time-extend local seismic catalogs, and their...
Major eruptions in the Andes are mainly characterized by the emission of large volumes of gas and volcanic ash. The plume may reach the stratosphere and be transported by winds. In Ecuador, the prevailing winds are westward, and the volcanic ash, also called tephra, is transported towards the Pacific Ocean. Vallejo (2011) studied tephra layers...