OVSICORI-UNA reported that an explosion at Turrialba at 1140 on 16 May generated gas-and-ash emissions, though the height of the plume was not determined due to fog. Wind models suggested that the ash plume rose 3 km above the crater and drifted WNW towards Valle Central. Officials on farms 2.5 km WNW reported abundant ashfall. Sustained tremor with significant and highly-variable amplitude continued to be recorded. On 17 May gas-and-steam emissions, intermittently but frequently containing ash, were recorded by the webcam. Throughout the day volcanic tremor amplitude decreased substantially, though numerous earthquakes continued to be recorded. Ash emissions gradually ended. At 1800 the seismic network began recording a large number of very-long-period earthquake, and at around 2200 volcanic tremor with significant amplitude was detected. Seismicity remained high the next morning.
Updated 2:40 pm CNE Turrialba
According to OVSICORI-A, the Turrialba volcano shows a radical change in the pattern of volcanic seismic tremor, he was now recorded harmonic tremor continuously from 13.00
The harmonic tremor reflects the movement of fluids (gas-liquid or even magma). Despite the change in the nature of the tremors, gas emissions, steam and ash remain at a relatively low height, not exceeding 200-300 meters above the summit.
The dispersion is to the southwest. So far, the farthest place comes the ash fall reports of San Gerardo de Irazu.
In addition, the CNE established a perimeter restriction of 5 km around the crater of the Turrialba volcano, as a precaution.
The scientific-technical agencies and the CNE maintain constant monitoring of volcanic activity, as well as coordination with the Municipal Emergency Committee Turrialba (CME).
Activity at Turrialba Volcano, located some 50 kilometers east of the capital, San José, increased significantly on Thursday with constant emanations of ash and at least three big explosions.
According to the University of Costa Rica’s National Seismological Network (RSN), the first explosion occurred at 2:05 p.m. and formed a plume of gas and ash that reached nearly 1 km high.
The second, and most prolonged one, occurred at 3:46 p.m. and lasted three minutes. A few minutes later, at 4:09 p.m., a third explosion was recorded.
The column of gases and ash at about 4:20 p.m. rose to more than 500 meters above the crater and wind conditions at that time caused ash to disperse from the volcano, mostly to the southwest, RSN reported.
Ash has been reported in San José and Heredia provinces.
Turrialba Volcano has seen increased activity following explosions in late April, some of which extended for several hours. The National University’s Volcanological and Seismological Observatory of Costa Rica (OVSICORI) reported that micro-tremors and ash eruptions from the volcano have been constant since an eruption recorded at 10:07 p.m. Wednesday.
On Wednesday, the National Emergency Commission (CNE) established a 5-km restricted access area around the volcano. Entrance to the Turrialba Volcano National Park has been closed to all visitors since 2014.
In a report, CNE geologist Blas Sánchez said ash and other materials from the explosions are visible on various farms located west of the volcano. He also reported that ash is accumulating in various nearby rivers.
May 20 , 2016. Turrialba , Costa Rica :
Elevation 3340 m
Source : GVP , CNE, Tico Times .