|Title||Location and size of the shallow magma reservoir beneath Klauea caldera, constraints from near-source V-p/V-s ratios|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||Lin G.Q, Amelung F., Shearer PM, Okubo P.G|
|Journal||Geophysical Research Letters|
|Type of Article||Article|
|Keywords||attenuation; california; continuous gps; earthquake; elastic properties; hawaiian volcanos; Kilauea; kilauea volcano; magma reservoir; saturated cracked solids; seismic tomography; structure; velocity; Vp; Vs|
We present high-resolution compressional wave to shear wave velocity ratios (V-p/V-s) beneath Klauea's summit caldera by applying an in situ estimation method using waveform cross-correlation data for three similar earthquake clusters. We observe high V-p/V-s ratios (1.832 and 1.852) for two event clusters surrounded by the low background V-p/V-s value of 1.412 at similar to 2.1km depth below the surface. These high and low V-p/V-s ratios can be explained by melt- and CO2-filled cracks, respectively, based on a theoretical crack model. The event cluster with the highest V-p/V-s ratio consists of long-period events that followed the 1997 East Rift Zone eruption, indicating their association with fluid and magma movement. The depths of the two clusters with high V-p/V-s ratios are consistent with the magma reservoir location inferred from geodetic observations. Their locations east and north of Halemaumau crater suggest a horizontal extent of a few kilometers for the reservoir.