Guagua Pichincha Report - from El Comercio Feb 18, 1999
Quito, Feb. 18,
1999
The Geophysical Institute of the Escuela Politécnica Nacional continues with the monitoring of the Guagua Pichincha is having daily explosions and earthquakes and experiencing renewed activity. The last cycle of activity started in the beginning of January and lasted for a week. We are now experiencing a new activity cycle, which is the fourth since October. Last Sunday (Feb. 14, 1999) there were 2 moderate phreatic explosions and more than 100 hybrid earthquakes.
This indicates that there is magma heat source that is still in disequilibrium. Although there are no new signs of magma rising, there is still the source of magma at 3 kilometers depth (shallow). The repeated explosions and the force of the fumaroles the past few days show the instability of the magmatic chamber. The explosions have been fairly constant during this month but, in the past few weeks, they have been more forceful. They are still not of the magnitude of those experienced from the 21st to the 27th of January. There are also harmonic tremors now (those that last in swarms of several hours) that have not been experienced for a month.
There have been 600 hybrid earthquakes in February (with 300 occurring yesterday, February 17). These are produced by the gas pressure showing that the magma chamber is degassing. The "plumbing" system is now being fractured even more from this activity according to Alex García who is coordinating the observations. Gracía comments that Pichincha is liberating some of the energy pent up over the past month. No one know exactly what is happening. Part of the problem is the lack of data about amount of material being thrown out. It is extremely dangerous at this point to get close to the crater. (Recently there have also been problems around the country with theft of antennas and batteries that service the monitoring stations)
At this point in time, Pichincha is experiencing one or two explosions per day. This is more than last months average but they are less intense. There are also fewer long period and volcano-tectonic earthquakes than at the beginning of the "Yellow Alert". The score card so far for the Guagua Pichincha Yellow Alert (started in October) is:
114 Explosions
297 Volcano-tectonic Earthquakes
920 Long Period Earthquakes
4851 Hybrid Earthquakes
____________________
Click your "BACK" button to return