Tremor Signals and Their Eruptive Event Characteristics: Case Study Popocatepetl Volcano (Mexico)

Seismic activity at Popocatepetl Volcano is characterized by a variety of signals in a wider frequency band (0.06s 30s), associated with its eruptive behavior. Since Popocatepetl reawakened in 1994 volcanic eruptive behavior has consisted of construction and destruction dome phases, strong volcanic degassing, and ash emissions ranged from small short-lived plumes rising a few hundred meters above the crater rim, to large plumes reaching 15 km above the crater with powerful ejection of ballistic projectiles associated with the destruction of lava domes. These eruptive events have been accompanied by persistent or spasmodic tremor signals before, during or after the eruption. Persistent tremor was first observed 22 hrs after the onset of explosions which marked the reawakening of Popocatepetl volcano on December 21, 1994, this kind of sustained tremor also occurred during lava effusion episodes. Tremor signals present a wide range of amplitudes and dominant periods in the range from 0.2-20~s, their duration may last from few minutes to days. We analyzed broadband records of tremor from stations of permanent and temporal networks associated with eruptive episodes occurred in May to July, 1997, September to December, 1998, and February to May and December, 2000. The tremor characteristics of these particular events are comparing with tremor episodes that are not related to eruption events and with sustained low-amplitude tremor observed to persist for hours. We correlate temporal, frequency and waveform characteristics of different tremor episodes with punctual measurements of sulfur dioxide emission rates, standard deviation and geochemistry analysis of ashes of the corresponding eruptive event. The results of correlation analyses indicate that tremor characteristics and properties of its associated eruptive event reflect conditions in the volcanic eruptive behavior and may help in monitoring eruptive dynamics.