Seismic attenuation studies provide important independent constraints on Earth properties since their sensitivity to temperature, fluids, compositional differences, and other rock properties is distinct from that provided by P- and S-wave velocities. Tomographic inversions are now commonly applied to determine the three-dimensional attenuation (quantified by 1/Q) structure in a manner comparable to velocity tomography.
(a) Northern California
We present a frequency-independent three-dimensional compressional wave attenuation model (indicated by quality factor Qp) for the crust and uppermost mantle of northern and central California (Lin, 2014). The resulting Qp model provides an important complement to the existing regional-scale velocity models for interpreting structural heterogeneity and fluid saturation of rocks in the study area.
(b) Salton Trough
A frequency-independent 3-D Qp model is developed for the Salton Trough and the adjacent San Jacinto Fault Zone (Lin, 2014). The new Qp model in this study provides a first-order measurement of the attenuation in the study area and serves as an important complement to the 3-D velocity model about rock properties and structure heterogeneity. The resulting Qp model provides an important complement to the existing regional-scale velocity models for interpreting structural heterogeneity and fluid saturation of rocks in the study area.
(c) Kilauea Volcano
We present a frequency-independent 3-D Qp model for Kilauea volcano, Hawaii, by inverting t* values using the simul2000 tomographic algorithm (Lin et al., 2015). We observe low Qp values at shallow depths (above 4 km) in the rift zones, which may be mainly attributed to the shallow intrusions. Both the Southwest and East Rift Zones are dominated by very high Qp values (up to 1000) at ~9 km depth, which indicate cooled magma or highly competent material that controls the magma ascent and evolution in Kilauea volcano. Active seismicity seems to be correlated with low Qp values. The availability of the 3-D Qp model provides a complementary description of the volcanic feeding system to the existing velocity models.
