Rapport sur les contributions - International Workshop on "Muon and Neutrino Radiography 2012" - IN2P3
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International Workshop on
”Muon and Neutrino
Radiography 2012”
Rapport sur les
contributions
https://indico.in2p3.fr/e/mnr2012International Wo … / Rapport sur les contributions Opening
Contribution ID: 1 Type: not specified
Opening
jeudi 19 avril 2012 09:00 (20 minutes)
April 16, 2020 Page 1International Wo … / Rapport sur les contributions social diner
Contribution ID: 2 Type: not specified
social diner
jeudi 19 avril 2012 20:00 (3 heures)
April 16, 2020 Page 2International Wo … / Rapport sur les contributions Muon tomography with resistive p …
Contribution ID: 3 Type: Oral
Muon tomography with resistive plate chambers
jeudi 19 avril 2012 17:10 (20 minutes)
Resistive Plate Chambers are widely used in high energy physics experiments as reliable trigger
systems due to their excellent time resolution and rate capability, while generally the track spatial
information is obtained by means of different detectors. Studies show that it is possible to produce
RPC with good spatial resolution (~ 0.5 mm) by appropriate choice of the pitch of the readout strips.
High resolution RPC (HRPC) can be economically produced to cover large area and represent a
valid alternative to more expensive detectors in applications when a spatial resolution of 0.5 mm is
sufficient. Our group has successfully produced a Muon Scattering Tomography (MST) prototype
based on 12 HRPCs which provide 3D information on muons scattering in a volume ~ 50 cm x 50
cm x 80 cm (suitable for scanning a suitcase). Both the incoming and the outgoing tracks of the
muon are reconstructed. The required spatial granularity is achieved using ~300 readout strips
per HRPC, with a pitch of 1.5 mm. All the strips from an HRPC are multiplexed into a single
differential analog line by four Helix 3.0 chips daisy chained on a hybrid circuit. The detector has
been collecting data since June 2011, with the HRPC showing an efficiency above 99% and purity
above 98%. The spatial resolution on the tracks is ~0.8 mm. This is a preliminary measurement
and includes the intrinsic detector resolution as well as the extrapolation errors due to multiple
scattering in the detectors and separation of the planes. Additional results will be presented.
Auteurs principaux: M. THOMAY, Christian (University of Bristol); Dr CUSSANS, David (Uni-
versity of Bristol); Dr VELTHUIS, Jaap (University of Bristol); Dr BAESSO, Paolo (University of Bris-
tol)
Orateur: M. THOMAY, Christian (University of Bristol)
Session Classification: Technical developments for muon and neutrino imaging
Track Classification: Technical developments for muon and neutrino imaging
April 16, 2020 Page 3International Wo … / Rapport sur les contributions CCC-based Muon Telescope for E …
Contribution ID: 4 Type: Oral
CCC-based Muon Telescope for Examination of
Natural Caves
jeudi 19 avril 2012 17:30 (20 minutes)
The REGARD group (Eötvös Loránd University and Wigner RCP RMI collaboration for R&D of
gaseous detectors) developed a portable detector for environmental application: searching for
large scale underground rock/soil inhomogenities [1]. The designed muontomograph is based
on the newly developed Closed Cathode Chamber (CCC) technology [2], which provide an cheap,
easy handling, portable, high-resolution detector system, able to work even at extreme conditions
(e.g. high humidity, low/high temperature). The developed muontomograph has about 0.1 square
meters of detection surface with 10 mrad angular resolution, but it is small enough to deploy within
difficultly-accessible cavern system where we used searching for hidden caverns.
Cosmic muon flux measurements had been performed using our muon telescope in natural caves:
(1) the relief reconstruction of the hill above the Molnár János cave in Budapest were done, (2)
unknown cavern searches in Ajándék Cave (Ariadne Cave System), Pilis Mountain, Hungary is
under investigation.
[1] G. G. Barnaföldi et al.: Portable Cosmic Muon Telescope for Environmental Applications, Sub-
mitted to Nucl. Instrum. Meth. A (March 2012)
[2] D. Varga, G. Hamar and G. Kiss:
Asymmetric multi-wire proportional chamber with reduced requirements to mechanical precision
Nucl. Instrum. Meth. A648, 163 (2011).
Auteur principal: M. OLÁH, László (Eötvös University)
Co-auteurs: Dr VARGA, Dezső (Eötvös Loránd University); Dr BARNAFÖLDI, Gergely Gábor
(Wigner RCP, Budapest); Dr SURÁNYI, Gergely (Geological, Geophysical and Space Science Research
Group of the HAS); M. HAMAR, Gergő (Wigner RCP, Budapest); M. MELEGH, Hunor Gergely (Bu-
dapest University of Technology and Economics)
Orateur: M. OLÁH, László (Eötvös University)
Session Classification: Technical developments for muon and neutrino imaging
Track Classification: Technical developments for muon and neutrino imaging
April 16, 2020 Page 4International Wo … / Rapport sur les contributions Density Muon Radiography of Sou …
Contribution ID: 5 Type: Oral
Density Muon Radiography of Soufrière of
Guadeloupe Volcano: Comparison with Geological,
Electrical Resistivity and Gravity data
mercredi 18 avril 2012 14:00 (20 minutes)
We present density radiographies obtained for the Soufrière of Guadeloupe lava dome, both in the
North-South and East-West planes. These radiographies reveal the highly heterogeneous density
structure of the volcano, with low-density regions corresponding to recognized hydrothermally
altered areas. The main structures observed in the density radiographies correlate with anomalies
in electrical resistivity cross-sections and density model derived from gravity data
Auteur principal: Prof. GIBERT, Dominique (Institut de Physique du Globe de Paris)
Co-auteurs: Dr NICOLLIN, Florence (Géosciences Rennes); Dr MARTEAU, Jacques (Institut de
Physique Nucléaire de Lyon); Prof. KOMOROWSKI, Jean-Christophe (Institut de Physique du Globe
de Paris); Dr LESPARRE, Nolwenn (Systems and Computer Engineering, Carleton University, Ottawa,
Canada); Prof. COUTANT, Olivier (Institut des Sciences de la Terre, Grenoble)
Orateur: Prof. GIBERT, Dominique (Institut de Physique du Globe de Paris)
Session Classification: Volcanology
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 5International Wo … / Rapport sur les contributions Application of Muon Geotomogra …
Contribution ID: 6 Type: Oral
Application of Muon Geotomography to Mineral
Exploration
jeudi 19 avril 2012 14:00 (20 minutes)
A novel geophysical imaging method using muon tomography is being developed for mineral
exploration. This nondestructive technique, similar in principle to computed tomography, can
be used to identify massive ore bodies underground. A proof-of-concept trial has been conducted
using a known volcanic massive sulfide deposit at Mt. Myra located on Vancouver Island in British
Columbia. Muon flux data from the experimental survey were used to obtain mass lengths from
the sensors to the surface. Using an accurate topographical map, the mass lengths were inverted to
reconstruct an image of the deposit in good agreement with the known drill-data. Simulations and
calculations were also performed to test the inversion software and design the survey. This work
demonstrates that muon tomography can be a valuable approach for identifying mineral deposits
with high-density contrast compared to the host rock.
Auteur principal: LIU, Zhiyi (AAPS@TRIUMF)
Co-auteurs: Prof. BRYMAN, Douglas (University of BC); Dr BUENO, James (Advanced Applied
Physics Solutions)
Orateur: LIU, Zhiyi (AAPS@TRIUMF)
Session Classification: Applications of muon imaging in geophysics, archeology, civil and
industrial engineering
Track Classification: Applications of muon imaging in civil and industrial engineering
April 16, 2020 Page 6International Wo … / Rapport sur les contributions Inverse problems for reconstructio …
Contribution ID: 7 Type: Oral
Inverse problems for reconstruction in tomography
vendredi 20 avril 2012 10:50 (25 minutes)
Iterative reconstruction in tomography, based on inverse problems approaches, have long proven
their potential to enhance reconstruction quality, compared to the filtered backprojection (FBP).
The drawback of iterative methods is their expensive computation time. However ongoing re-
searches on algorithms and recent enhancements in computational power, call for a re-evaluation
of the potential of iterative reconstruction in this domain.
I will present the advantages of using the inverse approach in tomographic reconstruction. A key
point is the data modelization, i.e. the numerical model of projection, which has to be sufficiently
accurate to ensure accordance to the data, while not enhancing too much the computational burden.
Combining the minimization of data residuals with an adequate regularization term can allow to
drastically reduce the angular sampling of projections without any loss of quality.
Auteur principal: MOMEY, Fabien (Centre de Recherche Astrophysique de Lyon - UCB Lyon 1 /
Laboratoire Hubert Curien - UJM Saint Étienne)
Orateur: MOMEY, Fabien (Centre de Recherche Astrophysique de Lyon - UCB Lyon 1 / Laboratoire
Hubert Curien - UJM Saint Étienne)
Session Classification: Tomographic reconstruction methods
Track Classification: Inverse problem in Appplied Mathematics
April 16, 2020 Page 7International Wo … / Rapport sur les contributions Development of a Logging Tool for …
Contribution ID: 8 Type: Poster
Development of a Logging Tool for Muon
Radiography
mercredi 18 avril 2012 09:00 (9h 30m)
A research for high level radioactive waste disposal should investigate geological structure and
saturation change of rock mass around a disposal cavern. In the CO2 geological storage and the
underground storage of crude oil, natural gas or liquefied petroleum gas (LPG), it is necessary to
monitor an upward migration of a gaseous fluid which is stored in underground. For an inves-
tigation of slope stability, it is effective to evaluate a high saturation area in the ground’s pore
space as the area should be the same as that of a rainfall infiltration. Since these phenomena
could be evaluated by a measurement of a density variation in underground rock, an application
of muon radiography is highly prospective. The Central Research Institute of Electric Power In-
dustry (CRIEPI) has a plan to conduct a field experiment to evaluate an applicability of the muon
radiography to engineering geology in cooperation with Electric Power Development Co., Ltd. (J-
POWER). The field experiment will be performed this year in slope topography. If the applicability
will be revealed as a result of the field experiment, CRIEPI will start a research on development of
a logging tool which can measure muon in a borehole. We plan to build a prototype of the logging
tool in around three years and will put it into practical use in around five years.
Auteur principal: SUENAGA, Hiroshi (Central Research Institute of Electric Power Industry)
Co-auteur: Prof. TANAKA, Hiroyuki (University of Tokyo)
Orateur: SUENAGA, Hiroshi (Central Research Institute of Electric Power Industry)
Session Classification: Poster Session
Track Classification: Applications of muon imaging in civil and industrial engineering
April 16, 2020 Page 8International Wo … / Rapport sur les contributions Development and evaluation of a …
Contribution ID: 9 Type: Poster
Development and evaluation of a time-dependent
radiographic technology by using a muon read out
module
mercredi 18 avril 2012 09:00 (9h 30m)
We will present a real-time monitoring system for cosmic-ray muon radiography as an application
of a readout module developed by T. Uchida et al [1,2]. The readout module was developed origi-
nally for probing the internal structure of volcanoes in 2008 [3]. Its features are small in size, low
power consumption, and the capability to access remotely via Ethernet. The current statistics data
of cosmic-ray muons can be read from a PC placed far from the module at anytime. By using this
feature, we constructed a real-time monitoring system. As a test experiment, we observed fluid
movement in a cylinder with a diameter of 112 meters water equivalent.
In this work, we succeeded to resolve the fluid movement in the cylinder. We varied the fluid level
inside the cylinder and measured the muon intensity. We found that the muon intensity correlates
inversely with the fluid level: the muon intensity increases for the lower fluid level and decreases
for the higher fluid level. Although the time resolution of muon radiography was sufficient to
resolve changes in the fluid level, an adequate time window has to be chosen for different operating
conditions. We anticipate that this system will be applicable to exploring high-speed phenomena
in a gigantic object.
References
[1] T. Uchida, H. K. M. Tanaka, and M. Tanaka, Space Saving and Power Efficient Readout System
for Cosmic-Ray
Muon Radiography, IEEE Transactions on Nuclear Science, Vol. 56, No.2, pp. 448-452, Apr., 2009.
[2] T. Uchida, H K. M. Tanaka, and M. Tanaka, Development of a muon radiographic imaging
electronic board
system towards a stable solar power operation, Earth Planets Space, Vol. 62, No. 2, pp. 167-172,
Feb., 2010.
[3] H.K.M. Tanaka, T. Uchida, M. Tanaka, and H. Shinohara, Cosmic-ray muon imaging of magma
in a conduit:
Degassing process of Satsuma-Iwojima Volcano, Japan, Geophysical Research Letters, Vol. 36,
L01304, pp. 1-5,
Jan., 2009.
Auteur principal: M. KUSAGAYA, Taro (Earthquake Research Institute, University of Tokyo)
Co-auteurs: Prof. TANAKA, Hiroyuki (University of Tokyo); Dr TANAKA, Manobu (High Energy
Accelerator Research Organization (KEK), Japan); Dr UCHIDA, Tomohisa (High Energy Accelerator
Research Organization (KEK), Japan)
Orateur: M. KUSAGAYA, Taro (Earthquake Research Institute, University of Tokyo)
Session Classification: Poster Session
Track Classification: Technical developments for muon and neutrino imaging
April 16, 2020 Page 9International Wo … / Rapport sur les contributions Rapid-time sequential muon radio …
Contribution ID: 10 Type: Poster
Rapid-time sequential muon radiography for
repetitional phenomena
mercredi 18 avril 2012 09:00 (9h 30m)
The time resolution of dynamic muon radiography is defined by achieving the appropriate angu-
lar resolution, detection area, and cosmic ray muon flux (=70 muons/m2 sr sec). For example, at
an angular resolution of 30 mrad, we need a detection area of 3.9 m2 to collect 100 muons in 8
hours for each bin. However, a space of this size in the correct position may be unavailable in
an industrial plant system. In this work, we developed a new technique to dynamically image a
high speed phenomenon using a more practically sized detector adapted to relieve some of these
restraints on the present system . This technique can be applied to any repetitional phenomena
by superimposing radiographs collected during different intervals of time. In the coarse of these
experiments, we collected muon data every 10 minutes in order to analyze the internal density
distribution of an electric furnace for different operating conditions. Here we report the results
for different (a) electric load conditions, (b) electric resistance conditions, and (c) production effi-
ciencies. We clearly distinguished the variation in the spatial distribution of the melt objects inside
the furnace collected between the daytime and the nighttime.
Auteur principal: Prof. TANAKA, Hiroyuki (University of Tokyo)
Orateur: Prof. TANAKA, Hiroyuki (University of Tokyo)
Session Classification: Poster Session
Track Classification: Applications of muon imaging in civil and industrial engineering
April 16, 2020 Page 10International Wo … / Rapport sur les contributions Neutrino Radiography of the Eart …
Contribution ID: 11 Type: Oral
Neutrino Radiography of the Earth’s Core with the
IceCube neutrino observatory
jeudi 19 avril 2012 11:10 (20 minutes)
In spring of 2011, the world’s largest neutrino observatory, IceCube, was completed within deep
glacial ice at the South Pole.
IceCube is designed to detect Cherenkov light emitted by secondary charged particles generated
from high-energy neutrinos.
The primary mission of IceCube is to discover the origin of cosmic neutrinos, while detailed studies
of the atmospheric neutrino background have been performed in the last five years. For example,
we observed ~35 atmospheric neutrino events per day in 2008 with a half-size detection volume of
completed IceCube.
From the point of view of geosciences, using atmospheric neutrinos seen by IceCube is currently
the unique solution to perform neutrino radiography for the Earth’s core.
This is the direct measurement of Earth’s core density, while the body-wave and the free oscillation
studies based on seismic wave measurements cannot reduce substantial uncertainties that depend
on geophysical models of Earth.
Two challenges to be overcome for IceCube are sufficient event statistics and improved energy
resolution.
Our current knowledge about Earth’s density profile, the Preliminary Reference Earth Model
(PREM), indicates sensitivity to neutrino energies above 10TeV. However, the atmospheric neu-
trino energy spectrum decreases steeply with increasing energy.
This constraint results in a requirement of long-term measurement even with a cubic kilometer
neutrino observatory.
Using 10 years of full-size IceCube data, we currently expect at least 3-sigma separation in aver-
aged density between core and mantle.
On the other hand, the energy resolution of event reconstruction affects separation efficiency of
neutrinos with energy over 10TeV.
With a better energy resolution and detailed understandings of systematic errors, the required
measurement period is minimized.
Our short-term goal is thus understanding systematic errors and improving our energy reconstruc-
tions.
In this talk we present the current status of neutrino radiography of the Earth’s Core with IceCube
one year data.
The talk will contain results performed with data obtained in 2008 or later.
Auteur principal: Dr HOSHINA, Kotoyo (ERI University of Tokyo)
Orateur: Dr HOSHINA, Kotoyo (ERI University of Tokyo)
Session Classification: Atmospheric Muons and Neutrinos
Track Classification: Earth and Planetary Science with muons and neutrinos
April 16, 2020 Page 11International Wo … / Rapport sur les contributions Visualizing the internal structure o …
Contribution ID: 12 Type: Oral
Visualizing the internal structure of a cryptodome
with cosmic ray muon radiography
mercredi 18 avril 2012 12:10 (20 minutes)
We have developed a multilayer, scintillator based, segmented muon hodoscope with the capacity
to create up to 8 layers. One of the most important processes of cosmic ray muon radiography is
the ability to select muon trajectories with precision from simultaneously arriving, vertical elec-
tromagnetic (EM) background components. As the size of the target increases, the muon path
length of the target lengthens and significantly decreases the flux of the penetrating muon. Ac-
cordingly, the effect of background (BG) noise becomes more exaggerated as the length of the
muon path increases. To address this issue, we attempted to reduce the vertical EM shower origi-
nated background events and to screen the low energy muons (muons with energies below 10 GeV)
by constructing a multi-layered, rotational muon hodoscope called GDM (gradient of density mea-
surement). Along with other adjustments, this GDM hodoscope was also designed to effectively
cancel artifacts in the PMT and scintillator individually as well as facilitating corrections for the
horizontal east-west effect. The maximum detectable thickness (MDT) of the present GDM was
found to be 4 km.w.e. Four or more position sensitive detector (PSD) layers measured the trajectory
of the cosmic-ray muons while low energy muons were screened using GDM analysis. Conven-
tional muon radiography methods require one to two months for data collection, however we were
able to measure the internal structure of the 1910 cryptodome of Usu volcano located in Hokkaido,
Japan in 290 hours with +/-2% precision in the density measurement. The obtained image indicates
the existence of high density magma that is hidden inside the structure of a hill.
Auteur principal: Prof. TANAKA, Hiroyuki (University of Tokyo)
Orateur: Prof. TANAKA, Hiroyuki (University of Tokyo)
Session Classification: Volcanology
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 12International Wo … / Rapport sur les contributions Volume slicing with multi- …
Contribution ID: 13 Type: Oral
Volume slicing with multi-directional muon
radiography
mercredi 18 avril 2012 15:40 (20 minutes)
Additional strategies to modify the rapid time measurement system of muon radiography may
make it possible to survey a target without knowledge of its exterior shape. Examples of such
targets would be an activated volcano with a growing lava dome or the geology of extraterres-
trial exploration. Established techniques of muon radiography rely on precise exterior shape data
because the method exclusively focuses on the integral density along the muon path. However,
the exterior shape specific targets may be changeable (as a lava dome grows) or may be unknown.
To resolve this point we need either (1) a time-sequential three dimensional exterior shape of the
target (e.g., as obtained by synthetic aperture rader measurement); or (2) a method to resolve the
internal density structure without the knowledge of an exterior shape. Unlike other phenomenon
utilized in geophysical techniques, muons pass through targets without diverging. Therefore, a to-
mographic analysis method using radon transformation can be applied. A new, portable, battery-
operated muon detector system with the capacity to create three-dimensional images of targets
without the aid of external shape information is described in this paper. Mt. Omuro was chosen
as an example in this survey because the structure is well known and, unlike other volcanoes, it
is encircled with road and parking areas that are conveniently situated. A battery-operated muon
detector was set up in a compact car and the target was measured by moving the car to different
vantage points. The measurement time at each point was 20 minutes, a suitable time frame to
assess a growing lava dome or to conduct an investigation at an extraterrestrial exploration point.
Once the reconstructed slice of the target was obtained, it was found to be consistent with the
known contours of the main structure and crater.
Auteur principal: Prof. TANAKA, Hiroyuki (University of Tokyo)
Orateur: Prof. TANAKA, Hiroyuki (University of Tokyo)
Session Classification: Volcanology
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 13International Wo … / Rapport sur les contributions Old and new perspectives for the r …
Contribution ID: 14 Type: Oral
Old and new perspectives for the readout system of
the MuRay muon telescope
jeudi 19 avril 2012 15:40 (20 minutes)
Muon telescopes, which detect atmospheric muons produced from cosmic ray showers, are pro-
viding an invaluable tool to volcanologists the world over by imaging the cone structure of the
volcanoes. An instrument of this type has been assembled in Italy by the MuRay collaboration.
The MuRay telescope uses scintillator rods to detect and track atmospheric muons. One of the
novelties with respect to other instruments developed for this purpose consists in the use Silicon
Photomultipliers (SiPM) to convert the scintillator light output in electrical signals.
In this paper a detailed description will be given of the electronics designed and built for this de-
tector based on the SPIROC chip, also new developments for the future using the new EASIROC
chip will be presented.
Auteur principal: D’ALESSANDRO, Raffaello (Università di Firenze - INFN Firenze)
Orateur: D’ALESSANDRO, Raffaello (Università di Firenze - INFN Firenze)
Session Classification: Technical developments for muon and neutrino imaging
Track Classification: Technical developments for muon and neutrino imaging
April 16, 2020 Page 14International Wo … / Rapport sur les contributions The MU-RAY telescope
Contribution ID: 15 Type: Oral
The MU-RAY telescope
mercredi 18 avril 2012 14:40 (20 minutes)
The MU-RAY project aims at the construction of muon telescopes and the development of new
analysis tools for muon radiography. The telescopes are required to be able to work in harsh
environment and to have low power consumption, good angular and time resolutions, large active
area and modularity. A high background suppression is required.
A prototype telescope has been constructed. The detector is composed of three stations, each
consisting of two planes of one square meter area for the measurement of the X-Y coordinates. The
three stations are assembled on a frame where their relative distance can be modified. The frame
can be easily rotated to change the azimuth angle. Each plane consists of two modules made by 32
scintillator strips of triangular cross section coupled with WLS fibres. The light emitted from fibres
is read by Silicon Photomultipliers, produced by FBK-IRST, mounted on a custom printed circuit
board. A dedicated front-end electronic, based on SPIROC ASIC, and data acquisition system have
been developed. The prototype is under test in the Physics Department in Naples.
The detector design, construction and preliminary performances results will be shown.
Auteur principal: AMBROSINO, Fabio (Dipartimento di Scienze Fisiche Università degli Studi di
Napoli ”Federico II” e Sezione INFN, Napoli)
Orateur: AMBROSINO, Fabio (Dipartimento di Scienze Fisiche Università degli Studi di Napoli ”Fed-
erico II” e Sezione INFN, Napoli)
Session Classification: Volcanology
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 15International Wo … / Rapport sur les contributions Development of a joint inversion t …
Contribution ID: 16 Type: Poster
Development of a joint inversion technique using
gravity and muon-radiographic data for resolving
three-dimensional density structure of a gigantic
body
mercredi 18 avril 2012 09:00 (9h 30m)
We have developed a method of analyzing gravity and muon-radiographic data for resolving a
three-dimensional density structure of a volcano. In the method, we search for a density structure
that explains the muon and gravity data by using a linear inversion scheme.
As a demonstration, we applied this method to Mt. Showa-Shinzan lava dome, Hokkaido, Japan.
At this site, muon observation has already been performed with emulsion cloud chamber(ECC).
The effective area of ECC was 1200 cm2, and the exposure time was four month. Tanaka et al.
[2007] calculated the amount of matter on the muon
trajectories in the unit of gcm^{-2} (density times length). In addition to the muon data, we newly
collected gravity data at 35 stations on/around the dome. The gravity data were measured by using
a LaCoste Romberg Gravimeter
(G-875). Positions of gravity stations were determined by GPS interferometry.
First, we performed a so-called checkerboard test with a synthetic data to test the resolution. We
concluded from the result of the test that a horizontal spatial resolution is about 200 m in our
configuration. Based on the conclusion, we conducted joint inversion of the actual muon and
gravity data.
The joint inversion yielded us the three-dimensional density profile of Mt. Showa-Shinzan. The
density profile suggested the two features of the dome. Firstly, we could visualize the high density
magma which had intruded beneath the dome at an altitude of 220 - 260 m. Secondly, we found
an ultra high density region which was suspected to be a spine spreading vertically near the top
of the dome.
Auteur principal: M. NISHIYAMA, Ryuichi (Earthquake Research Institute, University of Tokyo)
Co-auteurs: Prof. OSHIMA, Hiromitsu (Usu Volcano Observatory, Institute of Seismology and
Volcanology, Graduate School of Science, Hokkaido University); Prof. TANAKA, Hiroyuki (University
of Tokyo); Prof. OKUBO, Shuhei (Earthquake Research Institute, University of Tokyo); M. MAEKAWA,
Tokumitsu (Usu Volcano Observatory, Institute of Seismology and Volcanology, Graduate School of
Science, Hokkaido University); Prof. TANAKA, Yoshiyuki (Earthquake Research Institute, University
of Tokyo)
Orateur: M. NISHIYAMA, Ryuichi (Earthquake Research Institute, University of Tokyo)
Session Classification: Poster Session
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 16International Wo … / Rapport sur les contributions Earthquake tomography on volcan …
Contribution ID: 17 Type: Oral
Earthquake tomography on volcanoes with a
probabilistic regularization approach
mercredi 18 avril 2012 09:20 (20 minutes)
Muon radiography of volcanoes aims at estimating the density of rocks constituting the volcanic
edifice from muon fluxes. Earthquake tomography aims at estimating the seismic velocity of the
same rocks from the travel times of seismic waves. Muon radiography and earthquake tomogra-
phy are inverse problems that share some similar features - muon flux variation and travel time
may be both written as the integral of elementary flux variations or travel times across elementary
volumes of rocks that are sampled by muon trajectories or seismic rays.
In this talk we will present our experience in seismic tomography, emphasizing on the aspects
that may be later used in muon radiography. In both cases the whole volume of the volcanic
edifice may be incompletely or insufficiently sampled by muon trajectories or seismic rays. In-
ferring parameters characterizing elementary volumes from an integral measure therefore leads
to evidence trade-offs between this parameters. These trade-off relations feature the correlation
existing between the parameters, which is inherent to the nature of the inverse problem. Incom-
plete or insufficient sampling and trade-offs lead to find unphysical parameter values, which may
spread over trajectories or rays. Noise may therefore propagate along these trajectories or rays,
from poorly sampled elementary volumes to neighbouring elementary volumes due to the integral
nature of the muon flux variation or seismic travel time, lowering the resolution of the parameter
estimation.
Mitigating the problems due to the incomplete sampling of the studied volume is performed by reg-
ularizing the inversion. In this talk we will follow a probabilistic, bayesian approach for performing
this regularization, in the frame of seismic tomography. We therefore perform the Maximum a pos-
teriori Probability (MAP) estimation of the model parameters. Data and parameters are assumed to
follow a gaussian distribution, and a priori information is used to limit the values taken by parame-
ters to physical intervals. The correlation between parameters is explicitely taken into account by
defining correlation kernels and correlation lengths. Optimal standard deviation and correlation
length are found by minimizing a cost function. It leads to find the minimal-norm model fitting
the data. It will be shown that (1) introducing a limited bias in the estimation strongly limits its
variance, (2) contrarily to what is often thought, increasing the correlation length does not lead to
bias the model and to lower the resolution – instead, using the optimal correlation length leads to
increase the resolution by solving the bias-variance trade-off (improving the physical value of the
parameter while reducing the noise).
Auteur principal: Prof. GOT, Jean-Luc (ISTERRE, CNRS, Université de Savoie)
Co-auteur: Prof. VALETTE, Bernard (ISTERRE, CNRS, IRD)
Orateur: Prof. GOT, Jean-Luc (ISTERRE, CNRS, Université de Savoie)
Session Classification: Volcanology
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 17International Wo … / Rapport sur les contributions Introduction of a test measuremen …
Contribution ID: 18 Type: Poster
Introduction of a test measurement for a monitoring
technology inside a large-scale civil engineering
structure using muon radiography
mercredi 18 avril 2012 09:00 (9h 30m)
Introduction
The technology that enables us to observe the internal structure of a volcano and the city founda-
tion is being
developed by utilizing the muon’s significant penetration power. From the possibility to use this
technology for
the surveillance inside a large-scale civil engineering structure, we are planning an experimental
measurement.
General Instruction
A final target is safety judgment of the condition of a large-scale civil engineering structure. It is
important for
safety judgment to grasp the internal density contract, such as the crack and slack levels of a base
rock or the
structure, and degradation and groundwater levels.
However, feasibility of application of muon radiography to monitoring inside the large-scale civil
engineering
structure has not confirmed yet. Therefore, as a test experiment, we attempt to measure the fluc-
tuation of the
groundwater level in order to evaluate and examine the method.
Measurement will be carried out from the inside of a scupper tunnel in the base rock. The result
will be compared
with the independent groundwater level measurement in order to perform quantitative evaluation
of muon
radiography.
In addition, this test measurement will start the near future. About a detailed plan, it is under
examination now.
Auteurs principaux: Dr SANNOMIYA, Akira (Electric Power Development); Prof. TANAKA,
Hiroyuki (University of Tokyo)
Orateur: Dr SANNOMIYA, Akira (Electric Power Development)
Session Classification: Poster Session
Track Classification: Applications of muon imaging in civil and industrial engineering
April 16, 2020 Page 18International Wo … / Rapport sur les contributions The lava dome tomography in Unz …
Contribution ID: 19 Type: Poster
The lava dome tomography in Unzen : the discussion
about the observation and data treatment
mercredi 18 avril 2012 09:00 (9h 30m)
S. Miyamoto (7), C Bozza (6), N D’Ambrosio (1), G De Lellis (4), A Di Crescenzo (4), N Di Marco
(1), U Kose
(5), N Naganawa (3), M Nakamura (3), R Rescigno (6), A Russo (4), H Shimizu (2), C Sirignano (1),
S Stellacci
(6), P Strolin (4), H Tanaka (7), and V Tioukov (4)
(1) INFN , Gran Sasso, Italy, (2) SEVO, Kyushu University Japan, (3) F-lab, Nagoya University, Japan,
(4) INFN, Napoli,
Italy, (5) INFN , Padva, Italy, (6) INFN , Salerno, Italy, (7) ERI, The Univesity of Tokyo, Japan
The observation of the lava dome density 2D map was performed by using cosmic-ray muon and
muon detector in
Unzen. The muon detector, nuclear emulsion films which has high position resolution and 0.85m2
effective area,
was installed in a natural cave from early December 2010 to the end of March. The developed
nuclear emulsion
films has been scanned by automated muon readout system.
In this session, the flow of data acquisition, basic treatment of the data, and density calculation
will be shown. A
lot of discussions about this observation and data treatment are welcome.
Auteurs principaux: Prof. TANAKA, Hiroyuki (University of Tokyo); Dr MIYAMOTO, Seigo
(University of Tokyo)
Orateur: Dr MIYAMOTO, Seigo (University of Tokyo)
Session Classification: Poster Session
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 19International Wo … / Rapport sur les contributions The non-destructive measurement …
Contribution ID: 20 Type: Oral
The non-destructive measurement of soil water
content of upper part of the cave using soft
component of air shower
jeudi 19 avril 2012 17:50 (20 minutes)
We have developed a new radiographic method to measure the time variation of the water content
of the soil with soft component of air shower.
Air shower produced by a primary cosmic ray consists of hard component and soft component.
Hard component is mainly consists of muon, and soft components is consists of electron, positron
and photon. The penetration power of soft component is weaker than that of hard component,
so soft component is suitable for small scale structure thinner than 2 kg/cm^2 equivalent to 20m
thick water, like buildings and small hills. But it requires particle identification which means dis-
tinguishing hard component and soft component. Particle identification can be done with strong
magnets and dense detectors, but it is very hard to use that kind of detector for radiography be-
cause of their weight and cost.
We established the cheap and effective method to distinguish soft component and hard compo-
nent statistically. We also performed measurements in Arimura observation pit of Mt. Sakurajima,
Japan. As a result of this observation, we found there is an anti-correlation between soft compo-
nent flux and rainfall. If the water content of the soil became larger, the amount of absorption
increases. So this result can be interpreted as detecting the increase of the water content by soft
component flux.
This method can be applied for the quantitive compensation of the measurement data like abso-
lute gravitymeter data and tiltmeter data which is easy to receive turbulence by rain. It is also
expected that the quantitive compensation leads to the improvement in accuracy of diastrophism
measurement and the improvement in presumed accuracy of magma movement inside a volcano.
We will report this newly developed radiography method using soft component for small scale
structure in detail and the result of measurement. Further improvement and possible application
are also discussed.
Auteur principal: M. TAKETA, Akimichi (ERI, University of Tokyo)
Co-auteurs: Dr TANAKA, Hiroyuki . K. M. (ERI, University of Tokyo); Dr OKUBO, Shuhei (ERI,
University of Tokyo)
Orateur: M. TAKETA, Akimichi (ERI, University of Tokyo)
Session Classification: Technical developments for muon and neutrino imaging
Track Classification: Technical developments for muon and neutrino imaging
April 16, 2020 Page 20International Wo … / Rapport sur les contributions Geoneutrinos
Contribution ID: 21 Type: Oral
Geoneutrinos
jeudi 19 avril 2012 10:20 (25 minutes)
Electron anti-neutrinos produced by natural radioactivity inside the Earth - geoneutrinos - can
be used as a unique direct probe in order to determine the amount of long-lived radioactive ele-
ments inside our planet and to constrain the radiogenic contribution to the terrestrial heat. The
composition of the Earth’s interior, the heat sources driving the mantle convection, the genera-
tion of the Earth’s magnetic field are all not well understood, but in many models the abundance
of radioactive elements is one of the key points. Geoneutrinos with extremely small interaction
cross sections propagate undisturbed through the Earth and today represent the only possibility
how to trace down radioactivity in the deep Earth. The large volume liquid scintillator detectors,
originally built to measure neutrinos or anti-neutrinos from other sources, are capable to detect
them, as was demonstrated by KamLAND (Japan) in 2005 for the first time. Since then geoneu-
trinos were measured with high statistical significance both by KamLAND and by the Borexino
underground experiment (central Italy) designed to measure low energy solar neutrinos. Several
future projects of large volume detectors have geoneutrinos among their scientific goals, as SNO+
(in construction phase) or LENA and HanoHano. The status-of-art and scientific potential of this
new inter-disciplinary field will be presented.
Auteur principal: Dr LUDHOVA, Livia (INFN Milano)
Orateur: Dr LUDHOVA, Livia (INFN Milano)
Session Classification: Atmospheric Muons and Neutrinos
Track Classification: Earth and Planetary Science with muons and neutrinos
April 16, 2020 Page 21International Wo … / Rapport sur les contributions Muon radiography of the Unzen v …
Contribution ID: 22 Type: Oral
Muon radiography of the Unzen volcano with a
nuclear emulsion detector.
mercredi 18 avril 2012 14:20 (20 minutes)
The improvements of automated scanning systems have produced an impressive revival of the
nuclear emulsion technique, thus allowing their large scale application in particle physics experi-
ments. The
portability of a nuclear emulsion based detector makes it well suitable also for the muon radiogra-
phy of internal structures of volcanoes. We present the application of this technique to the study
of the Unzen and Stromboli volcanoes. We will report preliminary results on the analysis of emul-
sion films exposed in Japan and being currently scanned in Italian and Japanese laboratories. For
the Stromboli we present the design of the emulsion detector and the plans for the future analysis.
Auteur principal: Dr RUSSO, Andrea (INFN Napoli)
Orateur: Dr RUSSO, Andrea (INFN Napoli)
Session Classification: Volcanology
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 22International Wo … / Rapport sur les contributions Inner structure of the Puy de Dôm …
Contribution ID: 24 Type: Oral
Inner structure of the Puy de Dôme:
cross-comparison of geophysical models (ERT,
Gravimetry, Muonic Imagery)
mercredi 18 avril 2012 11:30 (20 minutes)
Muon imagery of volcanoes and other types of geological structures is presently actively developed
by several groups in the world. It has the potential capability to provide the 2D or 3D distribution
of density with an accuracy of a few percent. However, at this stage of the development of the
method, comparisons with the results from established geophysical methods are necessary to val-
idate its results. An experience is presently carried out at the Puy de Dôme volcano involving the
concurrent acquisition of muon imagery, electrical resistivity, 2D tomography (ERT) and gravity
survey. Here we present the preliminary results for the last two methods.
The Puy de Dôme is an 11,000 years old, 1465 m high composite dome in the Chaîne des Puys
(France). Geological studies suggest an evolution with at least two pulses of lava extrusion, sep-
arated by a partial destruction of the first construction. This interpretation is in good agreement
with the present morphology, as, for example, it can be observed in the new high precision LI-
DAR elevation model (50 cm resolution). In addition, Miallier and al., (2010) suggest that a final
explosive episode formed a small crater on the summit at 10,700 years. Hydrothermal alteration is
widespread on the outcrops in the summit area of the dome.
A first south-north resistivity section has been obtained in June 2011 using a 2200 m long line of
electrodes (electrode spacing of 35 m and of 5 m in the summit area). A second west-east similar
profile is planned for April 2012. These electric data will provide models of the distribution of
the resistivity values down to the base of the dome. Because the resistivity of the rocks varies
significantly (several orders of magnitude) according to their water and clay contents, a resistivity
section can be interpreted as a geological section. A detailed gravity survey has also been carried
out in March 2012. The dome and its surroundings are now covered with more than 250 gravity
stations. The computed Bouguer anomaly can be interpreted by models of the density distribution
within the dome. This will be directly comparable with the results from the muons imagery. Our
ultimate goal is to derive a model of the dome using the joint interpretation of all the sets of data.
Auteur principal: PORTAL, Angélie (OPGC-LMV)
Orateur: PORTAL, Angélie (OPGC-LMV)
Session Classification: Volcanology
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 23International Wo … / Rapport sur les contributions From conduit processes to surface …
Contribution ID: 25 Type: Oral
From conduit processes to surface emissions:
constraints from seismic and Doppler radar data
mercredi 18 avril 2012 09:40 (20 minutes)
We have investigated the dynamics of volcanic explosive eruptions, from the sub-surface source
mechanisms through to the surface emission dynamics. To this end, we carried out a cross-
correlation of broadband seismic data and ground-based Doppler radar data (VOLDORAD) recorded
at Arenal (Costa Rica). Arenal is a small stratovolcano ca. 1.1 km in height, characterized by a
mildly-explosive activity which commonly expels both ash plumes and ballistic projections that
can rise up to a few hundred meters above the vent. The radar data inform on the mass loading
and velocimetry of the expelled ejecta through time and space, while the seismic data inform on
volcanic processes operating within the edifice. A conceptual model is proposed to account for the
complex interplay of both data, whereby fractures through a rigid lava cap control the system’s
degassing, which in turn governs both the seismic and radar signals.
Auteur principal: Dr VALADE, Sebastien (LMV, Université Blaise Pascal)
Co-auteurs: Prof. HARRIS, Andrew (LMV, Université Blaise Pascal); Dr DONNADIEU, Franck (LMV,
Université Blaise Pascal); Prof. LESAGE, Philippe (ISTerre, Université de Savoie)
Orateur: Dr VALADE, Sebastien (LMV, Université Blaise Pascal)
Session Classification: Volcanology
Track Classification: Applications of muon imaging in volcanology; multi-probe structure
study of volcanoes
April 16, 2020 Page 24International Wo … / Rapport sur les contributions Exploring muon radiography as an …
Contribution ID: 42 Type: not specified
Exploring muon radiography as an asset in the
characterisation of activity at dome-forming
volcanoes
mercredi 18 avril 2012 15:00 (20 minutes)
Auteur principal: Dr GOTTSMANN, Joachim (University of Bristol)
Orateur: Dr GOTTSMANN, Joachim (University of Bristol)
Session Classification: Volcanology
April 16, 2020 Page 25International Wo … / Rapport sur les contributions Spinning Registration Reconstruct …
Contribution ID: 45 Type: not specified
Spinning Registration Reconstruction Quantization,
a new reconstruction method for electron
tomography
vendredi 20 avril 2012 11:15 (25 minutes)
SRRQ (Spinning Registration Reconstruction Quantization) is a reconstruction method alternat-
ing projections alignment and segmentation of reconstructed volume. This method reconstructs
alternately and iteratively an object complying a priori constraints, and an object which some pro-
jections comply registrated projections known experimentally. A priori constraints are derived
for an object to reconstruct which is piecewise constant and which has a known limited number
of phases. SRRQ well manages missed wedge reconstruction and misaligned projections which
are typical constraints of electron tomography. In this talk, we present the SRRQ method and give
some results on 2D simulations.
Auteur principal: Dr MOREAUD, Maxime (IFP Energies nouvelles)
Orateur: Dr MOREAUD, Maxime (IFP Energies nouvelles)
Session Classification: Tomographic reconstruction methods
Track Classification: Inverse problem in Appplied Mathematics
April 16, 2020 Page 26International Wo … / Rapport sur les contributions Integral Equation Methods for Ele …
Contribution ID: 46 Type: not specified
Integral Equation Methods for Electrical Impedance
Tomography
vendredi 20 avril 2012 09:25 (25 minutes)
Electrical Impedance Tomography (EIT) is a non-invasive, low cost technology developed to image
the electrical conductivity distribution of a conductive medium. The technique works by perform-
ing simultaneous measurements of electric currents and voltages on the boundary of an object.
These are the data used by an image reconstruction algorithm to determine the electrical conduc-
tivity distribution within the object. Different materials display different electrical properties, so a
map of the internal conductivity can be used to infer the internal structure of the object under con-
sideration. EIT can therefore be used as a method of industrial, geophysical and medical imaging.
In this talk we present integral equation reconstruction methods suitable for smooth conductivity
distributions.
Auteur principal: Dr SEBU, CRISTIANA (OXFORD BROOKES UNIVERSITY)
Orateur: Dr SEBU, CRISTIANA (OXFORD BROOKES UNIVERSITY)
Session Classification: Tomographic reconstruction methods
Track Classification: Inverse problem in Appplied Mathematics
April 16, 2020 Page 27International Wo … / Rapport sur les contributions Internal architecture of La Réunio …
Contribution ID: 47 Type: Oral
Internal architecture of La Réunion (Indian Ocean)
inferred from geophysical data
mercredi 18 avril 2012 10:20 (20 minutes)
The island of La Réunion (Indian Ocean) is a large oceanic volcanic system of which most of the
volume is submerged. We present a study of its internal structure using geophysical methods. Sub-
aerial and marine gravity and magnetic measurements have been compiled with terrestrial-based
electromagnetic surveys. Geophysical models have been constructed using geological constraints
and results from previous geophysical interpretations. The magnetic data allow us to differentiate
the structures pre- and post-dating the Brunhes-Matuyama magnetic reversal (0.78 Ma). The main
gravity features are used to detect and characterize the dense intrusive complexes, and to derive
the internal structure of the coastal formations and of the submarine flanks. The electromagnetic
data allow us to determine the distribution of electrical resistivities which we interpret in terms of
water saturation of rocks, hydrothermal alteration and the presence of hydrated mineral.
At Piton de La Fournaise, the dense gravity coverage allows us to unambiguously distinguish the
shallow and deep sources. The shallow ones correspond to the filling of ancient depressions by
dense lavas flows, to the Central Cone, largely composed of low density material, and to a level of
breccias at the base of the large southern valleys. The deep structures are associated with intrusive
complexes within Les Alizés volcano and the Ancient Shield of the Piton de la Fournaise. Gravity
variations associated with the collapse of the Dolomieu crater in April 2007 are studied in terms
of mass displacements within the edifice. The analysis of magnetic anomalies suggests that the
products from Piton de la Fournaise are rather thin to the north and to the east of the massif. It
also indicates the presence of a body of weakly magnetized rocks underneath the central zone,
correlated with the presence of a hydrothermal system, well characterized by a dome of rocks
with low resistivity, and with an inferred shallow magma reservoir. Beneath the Ancient Shield,
a region of weak resistivity may correspond to an ancient hydrothermal system. The Piton des
Neiges is depicted as a huge volcano structured around a large hypovolcanic system (~20 km in
diameter and ~4 km thick). The blanket of Brunhes formations is not continuous over Piton des
Neiges and shows large thickness variations. Only the western flank, the summit zone and, to a
lesser degree the northern flank, present significant thicknesses of these products. Topographical
barriers predating Bruhnes-Matyama reversal, such as those created by collapses, or subsequent
large landsides could explain the discontinuous distribution of these formations at the scale of the
massif. In addition, we observe a close correlation between the extent of the intrusive complex
and the topographical depressions of the massif. This suggests a possible relationship between a
subsidence of the complex and that of the overlying formations.
On the immerged part of the volcanic system, two large ancient volcanic constructions are identi-
fied in the continuation of sub-aerial ones: (1) to the east of the Piton de la Fournaise (the eastern
flank of Les Alizés volcano) and (2) to the south-west of Piton des Neiges (Etang Salé Submarine
Ridge). At the land-sea transition, the coastal shelf is interpreted in terms of accumulation of
hyaloclastites and pillow-lavas, such as the examples of La Montagne Massif, to the north, or of
the offshore continuation of the rift zones, to the north-east and south-east of Piton de la Fournaise.
On the immerged flanks, gravity and magnetic analyses show that the four submarine bulges are
mostly composed of low density and brecciated material which correspond well to accumulations
of mass wasting deposits as proposed by geological studies.
At the scale of the entire construction, we have been able to reconstruct the morphology of the top
April 16, 2020 Page 28International Wo … / Rapport sur les contributions Internal architecture of La Réunio … of the submarine volcanic constructions and that of the top of the island at the Brunhes-Matuyama reversal. Auteur principal: Mlle GAILLER, Lydie (LMV-BRGM) Co-auteur: LÉNAT, Jean-François (UMR 6524 CNRS ”Magmas et Volcans”) Orateur: Mlle GAILLER, Lydie (LMV-BRGM) Session Classification: Volcanology Track Classification: Applications of muon imaging in volcanology; multi-probe structure study of volcanoes April 16, 2020 Page 29
International Wo … / Rapport sur les contributions Crustal structure of Guadeloupe Is …
Contribution ID: 48 Type: Oral
Crustal structure of Guadeloupe Islands and the
Lesser Antilles Arc from a new gravity and magnetic
synthesis
mercredi 18 avril 2012 10:00 (20 minutes)
Guadeloupe Island (West French Indies) is one of the twenty islands that compose the Lesser An-
tilles Arc, which results from the subduction of the Atlantic Ocean plate beneath the Caribbean
one. The island lies in a complex volcano-tectonic system and the need to understand its geologi-
cal context has led to numerous on- and offshore geophysical investigations. This work presents
the compilation and processing of available, on-land, airborne and marine, gravity and magnetic
data acquired during the last 40 years on Guadeloupe Islands and at the scale of the Lesser An-
tilles Arc. The overall dataset provides new Bouguer and reduced to the pole magnetic anomaly
maps at the highest achievable resolution. Regionally, the main central negative gravity trend of
the arc allows defining two subsident areas. The first one is parallel to the arc direction (~N160°E)
to the north, whereas the second unexpected southern one is oriented parallel to oceanic ridges
(N130°E). Along the Outer Arc, the long wavelength positive anomaly is interpreted, at least along
the Karukera Spur, as an up-rise of the volcanic basement in agreement with the seismic stud-
ies. To the NE of Guadeloupe, the detailed analysis of the geophysical anomalies outlines a series
of structural discontinuities consistent with the main bathymetric morphologies, and in continu-
ity of the main fault systems already reported in this area. Based on geophysical evidences, this
large scale deformation and faulting of the Outer Arc presumably primarily affects the Atlantic
subducting plate and secondarily deforms the upper Caribbean plate and the accretion prism. At
the scale of Guadeloupe Island, joined gravity and magnetic modeling has been initiated based on
existing interpretation of old seismic refraction profiles, with a general structure in three main
layers. According to our geophysical anomalies, additional local structures are also modeled in
agreement with geological observations: i) the gravity and magnetic signals confirm an up-rise of
the volcanic basement below the limestone platforms outcropping on Grande-Terre Island ; ii) the
ancient volcanic complexes of Basse-Terre Island are modeled with high density and reverse mag-
netized formations; iii) the recent volcanic centre is associated with formations consistent with the
low measured density and the underlying hydrothermal system. The EW models coherently im-
age a NNW-SSE depression structure in half-graben beneath Basse-Terre Island, its western scarp
following the arc direction in agreement with bathymetric and seismic studies to the north of the
island. The so-defined depressed area, and particularly its opening in half-graben toward the SW,
is interpreted as the present-day front of deformation of the upper plate associated with the recent
volcanic activity on and around Guadeloupe. Based on this regional deformation model, perspec-
tives are given for further integrated investigation of key targets to address the internal structure
and evolution of the Lesser Antilles Arc and Guadeloupe volcanic system.
Auteur principal: GAILLER, Lydie (LMV-BRGM)
Co-auteurs: MARTELET, Guillaume (BRGM); THINON, Isabelle (BRGM); LEBRUN, Jean-Frédérique
(UAG); MUNCH, Philippe (Université de Montpellier); BOUCHOT, Vincent (BRGM)
Orateur: GAILLER, Lydie (LMV-BRGM)
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