OVSICORI-UNA reported that the amplitude of seismic tremor at Rincón de la Vieja intensified on 17 April and then increased again on 25 April. The tremor signals were accompanied by long-period events occurring at a rate of sometimes hundreds per day. The intensities of the earthquakes were the highest recorded within the last five years. A total of 19 small eruptive events were recorded during 17-25 April and produced steam-and-gas plumes that rose as high as 2 km. Sulfur dioxide emissions began to increase on 21 April and increased more notably during 24-25 April, rising from around 77 tonnes per day (t/d) to around 493 t/d. Tremor amplitude fluctuated at high levels during 26-29 April, reaching a new peak at around 0200 on 28 April. Gas-and-steam emissions were continuous. The Alert Level remained at Level 3, Orange, the third highest level on a four-level scale.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
