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Elmer Ruigrok, Deyan Draganov and Kees Wapenaar. Part II: The new Malargüe seismic array. IS@AO Workshop, Cambridge, April 19 th 2011. MalaRRgu e: A large seismic array in the Malarg üe department Partial collocation with Pierre Auger Observatory 2012: temporary array of 80 stations
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Elmer Ruigrok, Deyan Draganov and Kees Wapenaar Part II: The new Malargüe seismic array IS@AO Workshop, Cambridge, April 19th 2011
MalaRRgue: A large seismic array in the Malargüe department Partial collocation with Pierre Auger Observatory 2012: temporary array of 80 stations >=2013: ‘permanent’ array Monitoring and imaging the subsurface Application of recently developed techniques International team of geophysicists MalaRRgue ICES
Outline • Why a seismic array in Malargüe? • How will we achieve high-resolution subsurface images?
Why a seismic array in Malargüe? • How will we achieve high-resolution subsurface images?
The missing seismic array … Swell Local waves Ocean waves Seismic arrays (Koper et al., 2010) Oceanic -> seismic waves Beamforming seismic waves -> sea state MalaRRgue, aim 1: monitoring the southern oceans
Peteroa volcano Volcano activity, September 2010 MalaRRgue, aim 2: imaging and monitoring the Peteroa volcano
Imaging challenges still to be addressed (Gilbert et al., 2006) Malargüe • Known • Moho depth • Our imaging targets • Moho topography • Basin topography • Nazca slab depth • Magma intrusions • Major faults MalaRRgue, aim 3: detailed imaging of the lithosphere
Local seismicity Regional seismicity Malargüe MalaRRgue, aim 4: localizing local seismic activity
Positioning with Pierre Auger stations PA particle detector Seismic station
Why a seismic array in Malargüe? • How will we achieve high-resolution subsurface images?
Illumination for passive seismology I A method using teleseismic arrivals
Illumination for passive seismology II A method using teleseismic arrivals Crust and upper mantle
Conventional method: receiver function Crust and upper mantle
Receiver function image Malargüe
New method: seismic interferometry, input ~3km Crust and upper mantle
Example response selection P and reverberations PP and reverberations Time-window and separate pre-processing
New method: seismic interferometry, output Subsurface reflectivity image (example) Further processing
A dense sensor network Malargüe • T-array • 2 orthogonal linear subarrays • 3 km inline spacing • 42 stations • ‘Basin’ setting
Illumination by earthquakes and storms I: Inline earthquakes II: Inline oceanic storms (Landes et al., 2010)
High-resolution subsurface imaging • Reflection imaging instead of conversion imaging • Dense sensor network • Using not only earthquake responses, but also storm-induced waves
Summary Large seismic array (80 stations) planned in the Malargüe department • Imaging subsurface • Monitoring the sea state in the SH • Monitoring volcanic activity • Monitoring local seismicity
PAO synergies • Facility and expertise exchange • Coupling atmospheric gravity waves with seismic waves? • Coupling lightening to seismic waves?