The South Pacific region is characterized by a broadly elevated seafloor known as the superswell. This has concentration of midplate volcanoes that experienced massive eruptions in mid‐Cretaceous period (90–120 Ma). These characteristics suggest presence large‐scale mantle plume beneath Pacific, called superplume. geometry, origin depth, temperature, and composition superplume remain controversial, however, mainly due to lack seismological data documents structure Pacific. Seismic stations...

Monowai submarine volcano is one of the three most historically active volcanoes Kermadec arc. Repeat multibeam surveys Cone from September 1998 and 2004 T wave data recorded by Réseau Sismique Polynésien network for same period document collapse subsequent regrowth cone within this 6‐a period. Grid differencing two bathymetric sets, acquired 6 a apart, reveals that landslide ∼2230 m long occurred between surveys, which postcollapse talus ridge (∼0.023 km 3 in volume) subsequently formed....

Repeated multibeam bathymetric surveys at Monowai Cone, a shallow submarine basaltic volcano and part of the Volcanic Center in northern Kermadec arc, were conducted 1998, 2004, 2007. These document dramatic depth changes including negative up to −176 m from two sector collapses positive +138 volcanic reconstruction near summit debris avalanche deposits downslope slide scars. One collapse occurred on SE slope between 1998 2004 with volume ∼0.09 km 3 , another SW 2007 ∼0.04 . The change due...

Abstract Les auteurs indiquent les Rf, dans 4 systèmes de dissolvants, divers cyclitols et composés apparentés. Ces substances se laissent toutes révéler par le réactif Tollens I (à chaud). cycloses sont sélectivement décelables réaction Scherer ‐ Gallois sur papier permet d'autre part déceler inositols inososes alors que traitements successifs du chromatogramme au moyen d' Acetobacter suboxydans d'un des réactifs on peut susceptibles d'oxydation biochimique.

We report measurements of long‐period P wave polarization ( pol ) in Australia and Tahiti made by combining modeling the deviation harmonic analysis. The analysis horizontal as a function event back azimuth may be used to obtain information about (1) sensor misorientation, (2) dipping discontinuities, (3) seismic anisotropy, (4) velocity heterogeneities beneath station. results from grid search using Snell's law suggest presence discontinuity stations CTAO CAN Australia. These are consistent...

We present a method for the rapid estimation of tsunami wave heights, either in deep Pacific Basin, or at specific shore locations. It uses database 260 pre‐computed scenarios generic sources distributed along trenches, and can provide an estimate heights within minutes location earthquake its moment. The is tested against set DART data, 51 maregraph records Tahiti Marquesas Islands. was used real time to successfully predict amplitudes Polynesia during 2011 Tohoku alert.

We conducted geophysical observations on the French Polynesian seafloor in Pacific Ocean from 2009 to 2010 determine mantle structure beneath Society hotspot, which is a region of underlying volcanic activity responsible for forming Islands. The network Tomographic Investigation by ARray Experiment hotspot (TIARES, named after most common flower Tahiti) composed multi-sensor stations that include broadband ocean-bottom seismometers, electro-magnetometers, and differential pressure gauges....

Early detection of the onset a caldera collapse can provide crucial information to understand their formation and thus minimize risks for nearby population visitors. Here, we analyse 2007 Piton de la Fournaise on La Réunion Island recorded by broadband seismic station. We show that this instrument ultra-long period (ULP) signals with frequencies in range (0.003-0.01 Hz) accompanied very-long (VLP) (between 0.02 0.50 prior during suggesting it is possible detect beginning at depth anticipate...

We report the detection, principally by French Polynesian seismic network, of hydroacoustic signals generated inside large icebergs, either 'parked' along Wilkes coast Antarctica in Indian Ocean, or drifting Southern Pacific Ocean between latitudes 55° and 65°S, during years 2002–2004. The can be classified into two very broad families, based on nature their spectra. A first group features prominently monochromatic signals, whose frequency can, however, fluctuate with time a single sequence...

The French Tsunami Warning Center (CENALT) has been in operation since 2012. It is contributing to the North-eastern and Mediterranean (NEAM) tsunami warning mitigation system coordinated by United Nations Educational, Scientific, Cultural Organization, benefits from data exchange with several foreign institutes. This center supported Government provides civil-protection authorities member states of NEAM region relevant messages for assessing potential risk when an earthquake occurred...

A temporary network of 10 broad-band seismic stations has been installed in French Polynesia for the Polynesian Lithosphere and Upper Mantle Experiment (PLUME). All were either on volcanic islands or atolls various archipelagos a manner which complements geographic coverage provided by regional permanent stations. The primary aim PLUME is to image upper mantle structures related plate motion hotspot activity. However, because its proximity all sites, ocean responsible high level noise data...

Abstract L'auteur décrit l'hydrogénation du scyllo‐ms‐inosose et DL ‐épi‐ms‐inosose au moyen borohydrure de sodium présente un essai d'explication théorique des résultats obtenus.

Abstract. The first tsunami hazard map of French Polynesia is presented here on the basis historical data, and numerical simulations. Polynesia, because its central position in most prone ocean, Pacific, strongly exposed to far-field tsunamis. As no previous study area had been conducted, we compiled catalogues all observations (14 events), tide gauges records (69 marigrams). emphasise higher associated Marquesas archipelago, but also deficiency robust data other parts Polynesia. recourse...

The seismic structure beneath the South Pacific superswell has not been well explored in spite of its significance for mantle dynamics. region is characterized by a topographic high more than 680 m [ Adam and Bonneville , 2005]; concentration hot spot island chains (e.g., Society Cook‐Austral, Marquesas, Pitcairn) whose volcanic rocks have isotopic characteristics suggesting deep origin; broad, low‐velocity anomaly lower that revealed tomography These observations suggest presence...

The three‐dimensional S ‐wave velocity structure beneath the South Pacific Superswell is obtained from joint broadband seismic experiments on ocean floor and islands. We collected only approximately 800 relative times of long‐period teleseismic SH ‐waves by using a waveform cross‐correlation 76 events occurring January 2003 to May 2005. conducted time tomography obtain 3D depths 1600 km. In resultant image, we find characteristic distribution low‐velocity regions. most prominent features are...

The tsunami caused by the 2007 Peru earthquake (Mw 8.0) provoked less damage than seismic shaking itself (numerous casualties due to in vicinity of Pisco). However, it propagated across Pacific Ocean and small waves were observed on one tide gauge Taiohae Bay (Nuku Hiva, Marquesas, French Polynesia). We invert seismological data recover rupture pattern two steps. first step uses surface find a solution for moment tensor, second body compute slip distribution source area. consist main patches...

Abstract We present a new tomographic image beneath the South Pacific superswell, using finite frequency P wave travel time tomography with global and regional data. The stations include broadband ocean‐bottom seismograph stations. shows slow anomalies of 200‐300 km in diameter most hot spots studied region, extending continuously from shallow upper mantle to 400 depth. Narrow weak are detected at depths 500–1000 km, connecting large‐scale lateral dimension 1000–2000 prevailing below 1000...

On 29 December 2000, a meteor entry in the atmosphere produced several bright lights sky of Tahiti and intense sonic booms around midnight local time. This event was detected by Laboratoire de Détection et Géophysique French Polynesian seismic network IS24 infrasound station operating for Comprehensive Test Ban Treaty Organization (CTBTO). Both infrasonic signals indicated that altitude meteor's last explosion ∼45 km. From wave azimuth incidence angle determined through data processing,...