General Volcanic Activity Thread!

[Gray-Wolf]

2 things SnowBear,

1/ due to the 'noise floor' EQ's shallower than 10km appear to be shifted down to 10 or 11km?

2/ P & S waves have difficulties when 'fluids' are encountered? S waves cannot pass through fluids and P waves get deflected/distorted

 

There are 3 measuring stations on La Palma and since yesterday we have begun to see 'asymmetric plots' of shallower quakes (as I say any EQ in the body of the island gets bumped down to the 10km /11km level?)

The most impacted monitoring station happens to be the one closest to the vent (El Paso?) & so I harbour concerns that what we are seeing is the invasion of the country rock by Magma intrusions? I'm not saying that the Magma itself is the 'Fluid' causing the distortions of the EQ plots but that the intrusion is the source of the EQ's as it invades the country Rock? (& why Sunday/yesterday was so active EQ wise?)

 

Past eruptions has left the island shot through with Sheet Dykes which helped to form massive cisterns of trapped ground water collected over tens of thousands of years of rainfall?(all water on La Palma is sourced from such reserves?)

My worry is intrusive Magma flashing to steam such reserves

 

If you've ever seen a pressure cooker blow you'll know such would not be good!!!

Edited October 26, 2021 by Gray-Wolf

[SnowBear]

7 hours ago, Gray-Wolf said:

2 things SnowBear,

1/ due to the 'noise floor' EQ's shallower than 10km appear to be shifted down to 10 or 11km?

2/ P & S waves have difficulties when 'fluids' are encountered? S waves cannot pass through fluids and P waves get deflected/distorted

 

There are 3 measuring stations on La Palma and since yesterday we have begun to see 'asymmetric plots' of shallower quakes (as I say any EQ in the body of the island gets bumped down to the 10km /11km level?)

The most impacted monitoring station happens to be the one closest to the vent (El Paso?) & so I harbour concerns that what we are seeing is the invasion of the country rock by Magma intrusions? I'm not saying that the Magma itself is the 'Fluid' causing the distortions of the EQ plots but that the intrusion is the source of the EQ's as it invades the country Rock? (& why Sunday/yesterday was so active EQ wise?)

 

Past eruptions has left the island shot through with Sheet Dykes which helped to form massive cisterns of trapped ground water collected over tens of thousands of years of rainfall?(all water on La Palma is sourced from such reserves?)

My worry is intrusive Magma flashing to steam such reserves

 

If you've ever seen a pressure cooker blow you'll know such would not be good!!!

Haven't studied the geology in The Canaries closely so you will know more than me. 

One thing I have noted today though is reports in chat of a 30cm rise in the land around the volcano, if that is confirmed then what we see so far is just a taster I think. 

Phreatomagmatic eruption? They haven't raised too many concerns on that unless sea water gets in, but who knows. 

[SteveB]

4.7 eq occurred just over 2hrs ago. 40km deep.

[matty40s]

 

[The PIT]

Etna showing who's boss

 

[matty40s]

On 26/10/2021 at 21:13, The PIT said:

Etna showing who's boss

 

4 days ago, reported above, some pyroclastic ejection too, luckily, not towards populated areas.

[Typhoon John]

La Palma, on twitter saying cone collapsed in earlier and then followed by 600m lava fountain. Must be the most activity yet. 

 

[SteveB]

Another 4.8 eq at 38km followed by many 3-4 eq at 10-11km. las palmas.

 

Edited October 27, 2021 by SteveB

[Guest]

20 minutes ago, SteveB said:

Another 4.8 eq at 38km followed by many 3-4 eq at 10-11km. las palmas.

 

It’s absolutely rumbling today, looks like the most active eq phase so far in the last 12hrs. 

[Guest]

8 hours ago, matty40s said:

4 days ago, reported above, some pyroclastic ejection too, luckily, not towards populated areas.

I was lucky enough to spend some time on Enta 10yrs ago and was told by a local geologist that pyroclastic activity is actually pretty rare. 

[SnowBear]

Latest report from Volcano Discovery. 26/10/21 20:54

Compared to yesterday, the visible activity at the vents has decreased somewhat today. Only one of the vents seems now to produce pulsating lava fountains and an ash plume has been rising to approx. 2-2.5 kilometers today. Surface lava flow activity near the vents has decreased a lot as well.
Last evening, following hours of intense activity from at least four vents, parts of the western crater walls at the vents collapsed and gave way to short-lived floods of lava on the slopes of the cone. Whether or not the visible decrease is caused by a decrease of magma supply at the moment, remains unknown.
One factor to consider is that such larger re-configurations at the vent create new conditions so that the arriving magma might more easily find new ways to enter existing or create new tubes, and remain hidden from direct view.
However, it is likely that currently, indeed less magma is reaching the surface, but is this a sign the eruption might be waning? Likely not, unfortunately: instead of slowly deflating (as the magma chamber is being emptied by the eruption), the ground near the eruption site has been rising significantly again. And quite dramatically so. If the station LP3 has a correct measurement, the ground rose 10 cm (!) since yesterday. If that amount of inflation is caused by more magma arriving from depth into shallower reservoirs than what is erupting, it would fit the picture of less activity at the vents.
It also fits the observation that the volcanic tremor remains high, at similar levels as the past days, meaning that the system is still being supplied sign significant amounts of magma each day.

What is not easy to interpret in this model is that earthquakes have decreased significantly in numbers at the same time. Compared to the past days'average, less than half as many quakes occurred in the past 24 hours, "only" about one hundred... To add to all this, one of the strongest quakes so far at magnitude 4.8 or 4.9 occurred this afternoon at 5.25 p.m. at 40 km depth. It was widely felt on the whole island.

 

La Palma, Canary Islands: eruption and seismic crisis Sep 2021 - news and activity updates

WWW.VOLCANODISCOVERY.COM

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La Palma, Canary Islands: eruption and seismic crisis Sep 2021 - news and activity updates

 

[SteveB]

10cm uplift with decreased activity at the vents,  sounds like a new vent might open soon with explosive activity?

[SnowBear]

18 minutes ago, SteveB said:

10cm uplift with decreased activity at the vents,  sounds like a new vent might open soon with explosive activity?

Not really sure, the video feed at the moment shows the active vent from yesterday has slowed a bit, but the vents behind are active again with volcanic lightning seen in the Ash cloud. Activity in the visible vent is no where near enough to cause lightning. 

Eq activity is still high, last hour (timestamp 27/10/22 07:10)..

(Mag/Depth Km) 3.4/11, 3.0/10, 2.6/11, 3.5/11, 2.9/10, 2.9/9, 3.5/11, 3.2/11, 3.9/11, 3.1/15, 3.6/37

So a lot of activity at around the 10km level, and still seeing eq at deeper levels too. 

 

 

Edited October 27, 2021 by SnowBear
Spelling

[SnowBear]

Seems to have settled into a fairly stable routine today. 

From what I can work out in the feed... 

Back vent with fairly robust gas eruptions. 

Next vent forward black ash emmissions.

Top vent with a more grey or ash/steam. 

Next vent forward a mix of ash and steam, lighter grey so more steam in the mix. 

Front vent mostly lava fountain and cone rebuilding with frequent gas burst tantrums. 

Large amount of lava being transported down the front of the cone out of sight in a ravine as indicated by the smoke and steam. 

While in this state at least its not threatening any further areas of La Laguna, but at any stage that could change with a slump, collapse or change in magma flow from below causing new vents or more explosive activity. 

Comparison in size? Cone is about 200-300m high, Etna, 3,300m+.

AfarTV feed 1 distance to camera is 3.5km, AfarTV feed 2 the distance to the camera on the pier is 6km.

[SnowBear]

For those interested in a read on The Canary Island hot spot. 

Canary Islands

WWW.MANTLEPLUMES.ORG

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The Canary islands are generally assumed to result from a plume but alternative theories have been suggested

 

Edited October 27, 2021 by SnowBear
Spelling

[SnowBear]

Last 24 hours eq activity La Palma(19.40 BST). 

During the past 24 hours, La Palma volcano was shaken by 5 quakes of magnitude 4.0 or above, 108 quakes between 3.0 and 4.0, and 81 quakes between 2.0 and 3.0.

Biggest quake today: 4.8 quake La Palma Island, 4.2 km southeast of Santa Cruz de La Palma, Spain, Oct 27, 2021 3:21 pm (GMT +1) 6 hours ago

Most recent quake: 2.7 quake La Palma Island, 13 km southeast of Los Llanos de Aridane, Spain, Oct 27, 2021 8:51 pm (GMT +1) 36 minutes ago

[Gray-Wolf]

 

Draw a triangle on a bit of paper.

That is a cross section of the ridge on La Palma?

Extend the base out either side and you have the plains around the base of the ridge

Put a dot in the middle of the triangle, that is the source of an Earthquake Now draw 'ripples, emanating out from that dot, these are the 'P & S' waves moving out from the source?

When they hit the sides of the Triangle they die out so only the ripples pushing out of the base of the triangle carry on on their way

Now place one measuring station on the ridge and one on the plains below?

What do each of the stations see of the 'energy' of that Quake? Do they see the same or does one get more energy directed its way than the other?

The station on the ridge is the 'Montana De La Brena' measuring station on La Palma

What I've described is the only way I can explain to myself 'How' Montana station gets to report some BIIIIG Quakes (borne out by the spectrograph readouts?) but the two stations down below on the plains do not?

Edited October 28, 2021 by Gray-Wolf

[SnowBear]

2 hours ago, Gray-Wolf said:

 

Draw a triangle on a bit of paper.

That is a cross section of the ridge on La Palma?

Extend the base out either side and you have the plains around the base of the ridge

Put a dot in the middle of the triangle, that is the source of an Earthquake Now draw 'ripples, emanating out from that dot, these are the 'P & S' waves moving out from the source?

When they hit the sides of the Triangle they die out so only the ripples pushing out of the base of the triangle carry on on their way

Now place one measuring station on the ridge and one on the plains below?

What do each of the stations see of the 'energy' of that Quake? Do they see the same or does one get more energy directed its way than the other?

The station on the ridge is the 'Montana De La Brena' measuring station on La Palma

What I've described is the only way I can explain to myself 'How' Montana station gets to report some BIIIIG Quakes (borne out by the spectrograph readouts?) but the two stations down below on the plains do not?

Not sure GW, but I do note they continually downgrade the initial magnitudes, so they may be aware of the differences you note and adjust accordingly via some formula. 

[SnowBear]

Not had a lot of time to look much today but major reconfiguration of the cone on La Palma since last night with vents clogging, slumps and increased lava flow. Eq appears f

To be about the same. 

Front vent now back to its blowtorch act. 

[matty40s]

Keep your eyes open at all times when travelling near a volcano.. 

 

[The PIT]

A rolling lava block gathers no moss.

The eruption is bucking the trend of shorter eruptions. Now day 41

[Allseasons-Si]

Here is some of the best bits of the La Palma volcano from last night from over 1 hour of recording edited...

 

[SteveB]

A couple of big quakes overnight,  both around 39km. One was reported as 5.1, but is being reviewed. 

[SnowBear]

2 hours ago, SteveB said:

A couple of big quakes overnight,  both around 39km. One was reported as 5.1, but is being reviewed. 

Moderate magnitude 5.0 earthquake at 35 km depth

30 Oct 06:29 UTC: First to report: VolcanoDiscovery after 5 minutes.

30 Oct 06:29: Now using data updates from EMSC

30 Oct 06:30: Now using data updates from IGN

30 Oct 06:37: Magnitude recalculated from 4.5 to 5.1. Hypocenter depth recalculated from 5.0 to 39.0 km (from 3.1 to 24 mi). Epicenter location corrected by 21 km (13 mi) towards W.

30 Oct 07:31: Magnitude recalculated from 5.1 to 5.0. Hypocenter depth recalculated from 39.0 to 35.0 km (from 24 to 22 mi). Epicenter location corrected by 1.2 km (0.8 mi) towards NW.

[Typhoon John]

The lava flow is back flowing onto the banana plantations. It would be good to see it reach the sea again and start building new land rather than seeing it destroy more towns.