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Using MEMS Sensors and Distributed Sensing For a Rapid Array Mobilization Program (RAMP) Following the M8.8 Maule, Chile Earthquake Jesse F. Lawrence (Stanford University), Elizabeth S. Cochran (University of California, Riverside) The Quake-Catcher Network (QCN) exploits recent advances in sensing technologies and distributed sensing techniques. Micro-Electro- Mechanical Systems (MEMS) triaxial accelerometers are very low cost and interface to any desktop computer via USB cable enabling dense strong motion observations. Shake table tests show the MEMS accelerometers record high-fidelity seismic data and provide linear phase and amplitude response over a wide frequency range. Volunteer sensing using distributed computing techniques provides a mechanism to expand strong-motion seismology with minimal infrastructure costs, while promoting community participation in science. QCN has approximately 2000 participants worldwide that collect seismic data using a variety of MEMS sensors internal and external to computers. Distributed sensing allows for rapid transfer of metadata from participating stations, including data used to rapidly determine the magnitude and location of an earthquake. Trigger metadata are received with average data latencies between 3-7 seconds; the larger data latencies are correlated with greater server-station distances. Trigger times, wave amplitude, and station information are currently uploaded to the server for each trigger. Following the 27 February 2010 M8.8 earthquake in Maule, Chile we initiated a QCN Rapid Aftershock Mobilization Program (RAMP) and installed 100 USB sensors to record aftershocks. The USB accelerators were deployed mainly in regions directly affected by the mainshock and were densely concentrated around ConcepciÃ³n. Using this data, we refined our triggering and event detection algorithms and tested, retrospectively, whether the network can rapidly and accurately identify the location and magnitude of the moderate to large aftershocks (M>4). Figure 1 illustrates QCN’s ability to grow rapidly, record large aftershocks, and produce useful results such as earthquake locations and ShakeMaps. These results suggest that MEMS sensors installed in homes, schools, and offices provide a way to dramatically increase the density of strong motion observations for use in earthquake early warning. With QCN’s low-latency real-time data collection strategy, future investigations with nextgeneration sensors will yield data pertinent to ground shaking, earthquake location, and rupture mechanics in near real-time. References Figure 1: Left: Accelerograms from a M5.1 aftershock of the 27 February 2010 M8.8 Maule, Chile earthquake recorded on QCN stations in the Bio Bio region. Top right: Number of earthquakes and cumulative number of QCN stations installed versus days after the mainshock. Bottom right: Shake map produced using QCN records to locate and estimate the magnitude of the aftershock. Cochran, E.S., J.F. Lawrence, C. Christensen, and R. Jakka, The Quake-Catcher Network: Citizen science expanding seismic horizons, Seismol. Res. Lett., 80, 26-30,2009. Cochran E., Lawrence J., Christensen C., Chung A., A novel strong-motion seismic network for community participation in earthquake monitoring, IEEE Inst & Meas, 12, 6, 8-15, 2009. Acknowledgements: This work was preformed with support from NSF-EAR1035919, NSF-GEO0753435, and an IRIS subaward. We thank the thousands of volunteer participants who make the Quake-Catcher Network possible. II-64 | 2010 IRIS Core Programs Proposal | Volume II | Earthquake Source Studies
Teleseismic Inversion for Rupture Process of the 27 February 2010 Chile (Mw 8.8) Earthquake Thorne Lay (University of California Santa Cruz), Charles J. Ammon (The Pennsylvania State University), Hiroo Kanamori (California Institute of Technology), Keith D. Koper (Saint Louis University), Oner Sufri (Saint Louis University), Alexander R. Hutko (Incorporated Research Institutions for Seismology) The 27 February 2010 Chile (Mw 8.8) earthquake is the fifth largest earthquake to strike during the age of seismological instrumentation. The faulting geometry, slip distribution, seismic moment, and moment-rate function are estimated from broadband teleseismic P, SH, and Rayleigh wave signals obtained from Global Seismic Network and FDSN stations. We explore some of the trade-offs in the rupture-process estimation due to model parameterizations, limited teleseismic sampling of seismic phase velocities, and uncertainty in fault geometry. The average slip over the ~81,500 km2 rupture area is about 5 m, with slip concentrations down-dip, up-dip and southwest, and up-dip and north of the hypocenter. Relatively little slip occurred up-dip/ offshore of the hypocenter. The average rupture velocity is ~2.0-2.5 km/s. References Lay, T., C. J. Ammon, H. Kanamori, K. D. Koper, O. Sufri, and A. R. Hutko (2010). Teleseismic inversion for rupture process of the 27 February 2010 Chile (Mw 8.8) earthquake, Geophys. Res. Lett., in press. Acknowledgements: This work was supported by NSF grant EAR0635570 and USGS Award Number 05HQGR0174. Maps of the finite-fault slip distributions obtained by inversion of (a) teleseismic P and SH waves and (b) teleseismic P waves, SH waves, and R1 STFs. The background map is the same as Figure 1, with the GCMT focal mechanism shown in the insets. The P and SH inversion allows for variable rake at each grid position, with the slip vectors for the hanging wall being shown, and their relative amplitudes contoured. The rupture velocity used for the P and SH inversion was 2.5 km/s and it was 2.25 km/s for the P, SH and R1 STF inversion. 2010 IRIS Core Programs Proposal | Volume II | Earthquake Source Studies | II-65
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volume ii - accomplishments Facilit
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volume ii - accomplishments Facilit
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CONTENTS Introduction..............
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Non-Volcanic Tremor along the Oaxac
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Detecting the Limit of Slab Break-o
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Lower Mantle, Core-Mantle Boundary
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• Non-Earthquake Seismic Sources
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acoustics community by permitting a
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Near-Surface Environments - Hazards
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Why Do Faults Slip? Emily Brodsky (
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Another probe of fault evolution is
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to provide a best match with the Gl
Page 26 and 27: tectonic disruption and mass accumu
Page 28 and 29: W3 ∆ 5 . A number of intriguing r
Page 30 and 31: thermal and compositional effects r
Page 33 and 34: Towards a Global School Seismic Net
Page 35 and 36: On-Line Seismology Curriculum for U
Page 37 and 38: Teachers on the Leading Edge: Earth
Page 39 and 40: USArray Education and Outreach in S
Page 41 and 42: From an IRIS Lecture Tour to a Gene
Page 43 and 44: Explorer Series Robert Bartolotta (
Page 45 and 46: Workshop “Earth System Science fo
Page 47 and 48: The IRIS Internship Cycle: From Int
Page 49 and 50: Community-Outreach Efforts in Data
Page 51 and 52: Site Reconnaissance for Earthscope
Page 53 and 54: jAmaseis: Seismology Software Meeti
Page 55 and 56: Near Real-Time Simulations of Globa
Page 57 and 58: FuncLab: A MATLAB Interactive Toolb
Page 59 and 60: Five Years of Distributing the Seis
Page 61 and 62: IRIS DMS Data Products, Beyond Raw
Page 63 and 64: Local Earthquakes in the Dallas-Ft.
Page 65 and 66: Epicentral Location Based on Raylei
Page 67 and 68: Analysis of Spatial and Temporal Se
Page 69 and 70: Exceptional Ground Motions from the
Page 71 and 72: The 2010 Mw7.2 El Mayor-Cucapah Ear
Page 73 and 74: Effects of Kinematic Constraints on
Page 75: Imaging of the Source Properties of
Page 79 and 80: The Global Aftershocks of the 2004
Page 81 and 82: The 17 July 2006 Java Tsunami Earth
Page 83 and 84: Seismic Cycles on Oceanic Transform
Page 85 and 86: Migration of Early Aftershocks Foll
Page 87 and 88: Apparent Stress Variations at the O
Page 89 and 90: Automated Identification of Telesei
Page 91 and 92: Evaluating Ground Motion Prediction
Page 93 and 94: Tremor Monitoring Aaron Wech (Unive
Page 95 and 96: Slow Slip and Tremor in the Norther
Page 97 and 98: 0 0.5 1 1.5 2 2.5 3 0 0.5 1 1.5 2 2
Page 99 and 100: Intimate Details of Tremor Observed
Page 101 and 102: Global Search of Triggered Tremor a
Page 103 and 104: Slab Morphology in the Cascadia For
Page 105 and 106: Source Analysis of the Memorial Day
Page 107 and 108: Iceberg Tremor and Ocean Signals Ob
Page 109 and 110: Elucidating the Stick-Slip Nature o
Page 111 and 112: Probing the Atmosphere and Atmosphe
Page 113 and 114: Volcanic Plume Height Measured by S
Page 115 and 116: Eruption Dynamics at Mount St. Hele
Page 117 and 118: A Search for the Lunar Core Using A
Page 119 and 120: Seismic Imaging of the Mt. Rose Fau
Page 121 and 122: Structure of the California Coast R
Page 123 and 124: Temporal Variations in Crustal Scat
Page 125 and 126: High-Resolution Locations of Trigge
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Adjoint Tomography of the Southern
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Crustal Structure of the High Lava
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Controlled Source Seismic Experimen
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Structural Interpretations Based on
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Optimized Velocities and Prestack D
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40 Crustal Structure beneath the Hi
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Controlled-Source Seismic Investiga
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Northward Thinning of Tibetan Crust
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An Integrated Analysis of an Ancien
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Crustal Velocity Structure of Turke
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Ambient Noise Tomography of the Pam
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Ambient Noise Monitoring of Seismic
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Mushy Magma beneath Yellowstone Ris
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Imaging the Seattle Basin to Improv
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Developing a Database of ENA Ground
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Lithospheric Layering in the North
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eflective zones on depthmigrated se
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FischerFig05.pdf 1 2/8/10 12:31 PM
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S-Velocity Structure of Cratons, fr
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Seismic Structure of the Crust and
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Subducted Oceanic Asthenosphere and
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Detecting the Limit of Slab Break-o
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Pn Tomography of the Western United
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3-D Isotropic Shear Velocity Model
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Seismic Anisotropy Associated with
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Anisotropy in the Great Basin from
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Source-Side Shear Wave Splitting an
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S-Velocity Structure of the Upper M
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Velocity Structure of the Western U
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Segmented African Lithosphere benea
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Imaging the Mantle Wedge in the Cen
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A Slab Remnant beneath the Gulf of
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Imaging the Southern Alaska Subduct
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Opposing Slabs under Northern South
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Effect of Prior Petrological Constr
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Global Azimuthal Seismic Anisotropy
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The Stratification of Seismic Azimu
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Upper Mantle Anisotropy beneath the
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The Teleseismic Signature of Fossil
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Seismic Anisotropy under Central Al
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Stress-Induced Upper Crustal Anisot
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Tau-p Depropagation of Five Regiona
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Mapping the Upper Mantle with the S
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Upper Mantle Structure of Southern
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The Africa-Europe Plate Boundary in
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The Isabella Anomaly Imaged by Eart
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Tomographic Image of the Crust and
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Small-Scale Mantle Heterogeneity an
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Mantle Heterogeneity West and East
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New Geophysical Insight into the Or
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The Plume-slab Interaction beneath
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Imaging the Shear Wave Velocity "Pl
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Slab Fragmentation and Edge Flow: I
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Mantle Shear-Wave Velocity Structur
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Discordant Contrasts of P- and S-Wa
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Upper Mantle Discontinuity Topograp
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Edge-Driven Convection beneath the
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Imaging Attenuation in the Upper Ma
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Three-Dimensional Electrical Conduc
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Core-Mantle Boundary Heat Flow Thor
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Constraints on Lowermost Mantle Ani
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Localized Double-Array Stacking Ana
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Waveform Modeling of D" Discontinui
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Absence of Ultra-Low Velocity Zones
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Moving Seismic Tomography Beyond Fa
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A Three-Dimensional Radially Anisot
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The Importance of Crustal Correctio
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Slabs Do Not Go Gentle Karin Sigloc
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Localized Temporal Change of the Ea
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Core Structure Reexamined Using New
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Large Variations in Travel Times of
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Observations of Antipodal PKIIKP Wa
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Regional Variation of Inner Core An
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Wide-Scale Detection of Earthquake
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