Volcanos

Roundup of Global Volcanic Activity:

Nishino-shima (Volcano Islands): The island continues to grow as lava flows slowly spread into several directions. This is shown nicely by the latest aerial survey pictures the Japanese Coast guard took on 28 Feb. The most active flow fronts are currently at the southern shore while advance on the northern and eastern margins of the flow field has slowed down. Two prominent cones have formed around the main vents, the smaller and younger of which still has strombolian activity as well. One can note the closure of a small bay that had been formed in early Feb by lava flow tongues; eventually, the two flows touched and separated the bay from open water, turning it into a small lake. Several other small bays present now (or, on 28 Feb, at least) are in the process of forming and probably become lakes as well in the future. The discoloration of the enclosed water comes from dissolved gasses and fine material in suspension. The fate of these lakes will depend on the evolution of the lava flows. If new flows cover them, they might well disappear as well.

Kilauea (Hawai'i): (3 Mar) Summit tiltmeters record weak inflationary tilt, the lava-lake level dropped slightly to around 39m (128ft) below the floor of Halema`uma`u

Pacaya (Guatemala): (3 Mar) The latest eruptive phase of the volcano continues at decreased strength. The second paroxysm of Pacaya this year, only about 6 weeks after the previous one in January, started yesterday morning with lava fountains, associated ash emissions, as well as a new lava flow that quickly reached about 2 km length. The current seismic signal suggests that activity continues at a decreasing trend. Images from later during yesterday showed that lava fountaining and lava effusion had already decreased significantly after the first hours. A new phase of increased activity at the volcano began today. Strombolian explosions became more intense, ejecting incandescent bombs to approx. 200 m above the crater, and since this morning, a new lava flow started to descend from the summit on the western flank. The activity surge is reflected by a strong, gradual increase of tremor. Eruptive activity continues at reduced intensity as the seismic signal indicates. As of yesterday, INSIVUMEH reported still active flows from the vent at the western base of the Mackenney cone. Their length was between 1300-1600 m and they reached the southern base of the cone. Weak explosions were observed at the summit vent.

Ubinas (Peru): According to the Geophysical Institute of Peru (IGP), magma has arrived near or at the crater of the volcano. This is indicated by a recent swarm of hybrid earthquakes and a weak thermal anomaly that has been detected at the summit during the past 3 weeks. In a press article, the head of IGP, Orlando Macedo, said that that based on the low energy of the seismic signals recorded, the quantity of new magma that has risen is estimated to be small and that the most likely scenario for the near to medium future are smaller (explosive) eruptions from the volcano.