.[1] Seismic data analysis is a powerful tool for remote characterization of rock slope failures. Here we develop quantitative estimates of fundamental rockslide properties (e.g., volume) based solely on data from an existing regional seismic network. We assembled a data set of twenty known rockslides in the central Alps (with volumes between 1,000 and 2,000,000 m 3 ) and analyzed their corresponding seismograms. Common signal characteristics include emergent onsets, slowly decaying tails, and a triangular spectrogram shape. The main component of seismic energy is contained in frequencies below ∼3-4 Hz, while higher-frequency signals may be caused by block impacts. Location estimates were generated using automatic arrival time picks and resulted in a mean location error of 10.9 km. A linear relationship for the detection limit of a rockslide as a function of volume was identified for our seismic station network. To estimate rockslide volume, runout distance, drop height, potential energy, and Fahrböschung (angle of reach), we extracted five simple metrics from each seismogram: signal duration, peak value of the ground velocity envelope, velocity envelope area, risetime, and average ground velocity. Using multivariate linear regression, the combination of duration, peak envelope velocity, and envelope area best estimated event parameters, with r 2 values ranging between 0.8 and 0.88. Three new rockslides were then used to validate our method, and volume, runout, drop height, and potential energy were estimated within the correct order of magnitude. When provided with a suitable data set of rockslide events, our method can be easily adapted to other regions and seismic networks.

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It has been proposed that a deep magma body beneath the east rift zone (ERZ) of Kilauea volcano, Hawaii, must be present in order to explain the observed deformation of the south flank. From November 1999 to June 2000, 29 IRIS-PASSCAL three-component seismographs were operated across Kilauea's ERZ and south flank. Using local earthquakes recorded by these stations, supplemented with data from the Hawaiian Volcano Observatory stations, we investigated the deep structure of the ERZ and south flank through two approaches: seismic velocity tomography and seismic attenuation tomography. Results along two north-northwest-south-southeast profiles are examined. The western profile shows a low-velocity region beneath and south of the Hilina Pali, and earthquakes at depth are sandwiched between a high V p /V s , high Q zone and a low V p /V s , low Q zone. The velocity and attenuation differences are interpreted to reflect the contrast in material properties between the overlying volcanic pile and the underlying fluid-rich ocean sediments and fractured, altered ocean crust beneath the south flank thrust fault. The eastern profile shows an anomalous feature with low V p , low V p /V s , high Q p , and low Q s at about 7 km depth beneath the ERZ. The low V p /V s ratio is inconsistent with the presence of partial melt. Instead, this anomaly is attributed to a trapped reservoir of CO 2. Our results do not support the existence of a sizable molten or partially molten body at depth beneath the ERZ. If the deep magma body exists, it must be relatively small. Based on synthetic resolution tests, an estimated limit on the maximum allowable crosssectional size of the deep magma body is about 2 by 4 km.