Activity of Nevado del Ruiz, Veniaminof, Semisopochnoi, La Fournaise, Krakatau and Merapi.

An extraordinary bulletin of the Servicio Geologico Columbiano / Manizales of September 17 / 1:10 local reports a new episode of continuous volcanic tremor, associated with ash emissions at Nevado del Ruiz since September 15.

The webcam images and the testimonies of the officials of the Los Nevados Natural Park confirm eruptive plumes reaching max. 1,400 meters above the summit, and a dispersion to the northwest and west.

The level of Amarillo activity is maintained.
 

Source: SGC Manizales & VAAC Washington

Nevado del Ruiz - 17.09.2018 / 15:34 - Volcanic Ash Advisory - Doc. VAAC Washington

In Alaska, the Veniaminof still emits a lava flow; the seismic data and the high surface temperatures recorded by satellite confirm this.

At Semisopochnoi, an almost constant tremor is recorded, without observation of volcanic activity by the satellites (but the weather is overcast), nor detected by the infrasonic system.

Both volcanoes remain alert Watch / Orange.

Source: AVO-USGS

At Piton de La Fournaise, the volcanic tremor (indicator of eruptive intensity on the surface), has remained at a relatively stable and low level since 18:00 on September 15 (14:00 UT), despite some variations in recent hours.

Two volcano-tectonic earthquakes were recorded beneath the summit craters during the day of 17 September, as well as three more during the current day.
The SO₂ emissions recorded by the permanent sensors of the OVPF are much higher than the atmospheric background (related to the plume of volcanic gas), and are today dispersed mainly towards the west since the beginning of the day.
No deformation is noticeable since the beginning of the eruption.
The surface flows were estimated from satellite data, via the MIROVA platform (University of Turin) and HOTVOLC (OPGC - University of Auvergne), and between 7 and 11 m³ / s on the day of 17 September. The casting front is still in the upper part of the enclosure and does not seem to have changed since yesterday. The pouring arm to the east seems to have widened on its northern flank. Another pouring arm flows south. His front does not seem to have progressed since yesterday. At the end of the morning, these two fronts of flows were maintained several hundred meters from the southern rampart of the enclosure. The easterly easter front is currently about 2km from the slope break.

In an interview with Clicanoo, Aline Pelletier confirms that the activity is part of an increased activity observed since 2014.

She reports that there is still a lot of magma in the magmatic reservoir of La Fournaise, since the first three eruptions of 2018 have very little drained.

The rise of magma from the depths is brought to light by the carbon dioxide concentrations in the far field, and "... It will be necessary that this magma come out, either during this eruption or during successive eruptions if this one had to stop. " (interview Clicanoo 18.09.2018)

Sources: OVPF & Clicanoo

A video of our Belgian friend John Van Marcke illustrates Krakatau's activity on September 13th.

In the photos below, we observe a lava flow, arriving at several points at sea, where the interaction between the lava and the water forms white plumes of steam and gases, all under a plume of gray ash.

At the seismicity level, the tremor was continuous on September 18, with a dominant amplitude of 40 mm (range: 2-45 mm)

The level of activity is 2 / Waspada, with a forbidden area of 1 km radius around the crater

Source: PVMBG

At Merapi, the growth of the dome continues; a slight degassing amounting to 20-50 meters above the crater is observed this morning 19 September.

Source: PVMBG