Characterizing complex eruptive activity at Santiaguito, Guatemala using infrasound semblance in networked arrays

We implement an infrasound semblance technique to identify acoustic sources originating from volcanic vents and apply the technique to the generally low-amplitude infrasound (< 3 Pa at 1 km) signals produced by Santiaguito dome in Guatemala. Semblance detection is demonstrated with data collected from two-element miniature arrays with ~ 30 m spacing between elements. The semblance technique is effective at identifying a range of eruptive phenomena, including pyroclastic-laden eruptions, vigorous degassing events, and rockfalls, even during periods of high wind contamination Many of the detected events are low in amplitude (tens of mPa) such that they are observed only by select arrays positioned with proximity and line-of-sight to the source. Larger events, such as the pyroclastic-laden eruptions, which occurred bi-hourly in 2009, were detected by all five arrays and produced an infrasonic signal that was correlated across the network. Network correlated events can be roughly located and map to the summit of the Caliente Vent where pyroclastic-laden eruptions originate. In general, the degree of Santiaguito infrasound event correlation is poor across the network, suggesting that complex source geometry contributes to asymmetric sound radiation.

Research Highlights
► Santiaguito Dome radiates low-intensity (<1 Pa at 1 km) infrasound during pyroclastic-laden eruptions and rockfall events.
► Infrasound is recorded variably across a network of distributed microphones suggesting a non-compact and complex sound source.
► Networked arrays of microphones and semblance techniques are effective for discriminating volcano signal from other sources of sound and ambient noise.
► Infrasound sources for various eruptive events are locatable and are spatially distributed around the 200-m diameter active vent.SynopsisThe stable molecule carbon dioxide can be photo cleaved by intramolecular electron transfer between suitable redox-active metal centers such as carbonate instead of carbon dioxide. After CT excitation the formation of stable products is determined by the availability of appropriate oxidation states at the metal centers.