Tirelessly updating Avalon on the El Hierro eruption.

[Amzer Zo]

Polly’s* latest:

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

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How it's looking like now from Las Puntas de La Frontera:

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For the last 10 days, it now shows whatever Polly is up to as far as seismic activity is concerned:

Since the beginning

New cumulative graph starting January 01, 2012. The continuously changing scales keeps compressing the earlier graphs to the bottom and to the left!

Location of the EQs for the last 10 days:

Since the beginning

Refresh your browser page to get the latest numbers and positions.[/B]

* : Polly was so named from the “polycephalic snake” look of the initial cumulative energy graph (see post # 327).
The name became most appropriate when the eruption from multiple mouths/vents/cones/heads started to develop.

[Amzer Zo]

New videos show the underwater volcano of El Hierro and the emission of gases in the area

Source: http://www.youtube.com/watch?v=VZGzNhuBCnE

A team from the CSIC and the IGN, with the collaboration of the crew of the Salvamar Adhara, Sea Rescue, has obtained new images of the underwater volcano of El Hierro and degassing process is observed in the shallow zone of the volcano.

"The images that follow show an intense degassing, which are often recognized manifestations (bubbling and greenish) on the surface of the sea by gases rising to the surface of the sea" they explain.

In the area there have been repeated filming at checkpoints to assess qualitatively the evolution of the degassing process. In the recorded images are recognized "the typical morphologies of submarine volcanic rocks and morphologies that correspond to volcanic cones and craters."

Source: http://www.youtube.com/watch?v=fUU7cRRSv1A

The film, being made systematically, allowed the team to the CSIC-IGN identify different types of lava and volcanic deposits and characterize the different areas of the volcanic structure. Specifically, in areas of intense emission of gases have been identified in the images some dead fish in the background.

The underwater camera used is of Spanish manufacture and design, resistant to gases and temperature in the work area has adapted to the needs of research in an area with rugged terrain and irregular.

From: http://www.lavozdelanzarote.com/article69708.html



Summary video uploaded by Presidencia Gob. de Canarias

Source: http://www.youtube.com/watch?v=Jxdcfcyu4Co

Note: Videos were edited and/or put together on May 2sd.

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

The squiggle at 10:12 above, is from this one in Chile:


--- MAG - UTC DATE-TIME ----- LAT -- LON -DEPTH ---- Region

MAP 6.2 2012/05/14 10:00:39 -17.816 -69.749 98.3 TARAPACA, CHILE

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

For the day: :



Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.


See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

All Canarian seismographs have been off lines since yesterday morning 9 am.

No idea when the data will be all caught up on?

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Interesting summary paper published by JC Carracedo et al and reproduced at Earthquakereport.com:


The 2011 submarine volcanic eruption in El Hierro (Canary Islands), Spain – Eruption overview

Last update: May 18, 2012 at 6:19 pm by By Armand Vervaeck



Dr. Juan Carlos Carracedo Gómez - ULPGC

Forty years after the Teneguía Volcano (La Palma, 1971), a submarine eruption took place off the town of La Restinga, south of El Hierro, the smallest and youngest island of the Canarian Archipelago. Precursors allowed an early detection of the event and its approximate location, suggesting it was submarine. Uncertainties derived from insufficient scientific information available to the authorities during the eruption, leading to disproportionate civil protection measures, which had an impact on the island’s economy based primarily on tourism, while residents experienced extra fear and distress.

[...]

Fig. 6. Sketch showing the structure of El Hierro Island and the 2011 events. Ascending magma that, according to the distribution of seismic events prior to eruption, moved sub-horizontally from north to south in the oceanic crust, is interacting with the pre-volcanic sedimentary rocks. The floating rocks found at El Hierro during the early days of the eruption are the products of magma– sediment interaction beneath the volcano. These ‘restingolites’ were carried to the ocean floor during eruption and melted and vesiculated while immersed in magma. Once erupted onto the ocean floor, they separated from the erupting lava and floated on the sea surface due to their high vesicularity and low density (from Troll et al., 2011).

[...]

Fig. 7. Scientific information available during the 2011 submarine eruption in El Hierro and civil protection measures taken.

The overall relatively low magnitude seismicity (the greater part of magnitudes < M 3.0), and the comparatively small and deep (> 150 m) basaltic submarine eruption seems thus to have caused surprisingly greater distress and economic loss than a similar magnitude eruption on land in 1971 (Teneguía Volcano, La Palma). This eruption was managed 40 years ago without disturbing the population to the same extent or causing economic hardship.

One explanation is that, in contrast to the 1971 Teneguía eruption, during the 2011 eruption accurate scientific information was not available at decisive points to dispel uncertainties and provide appropriate criteria to manage the situation (Fig. 7). The plan for volcanic emergencies by PEVOLCA tasks the National Geographic Institute (IGN) with managing the scientific aspects. IGN geophysicists analyzed and interpreted correctly the seismic precursors, allowing early detection of the time and approximate location of the eruption, and predicting it to be submarine. However, at the onset of the eruption a small group of scientists took charge to the exclusion of others, ignoring independent observations and data. Thus, objective scientific advice to enable the authorities to make the correct decisions at crucial points in time was not forthcoming.

This is best illustrated by the failure to anticipate the need for a survey vessel that could provide detailed information about the eruptive activity occurring under the sea. The first evacuation of La Restinga shortly after the onset of the eruption was probably ordered because the authorities had insufficient information about the distance and depth of the submarine vent, and were thus fearing the onset of explosive (surtseyan) activity.

Once the IEO vessel arrived the depth and main features of the submarine volcano were determined.

However, a lack of coordination between the scientific committee and the oceanographic research vessel resulted once more in incomplete information about the progress of the eruption and the proximity of the submarine vent to the surface. Strong bubbling and degassing, and abundant rock fragments resembling lava bombs found floating on the ocean surface on 5 November 2011 prompted the authorities to order the second evacuation of La Restinga (see Fig. 7), due to uncertainties regarding the involvement of ‘explosive’ high silica magma (the ‘restingolites’). A report by non-PEVOLCA scientists—involving chemical analyses of quartz crystals, which concluded these to be sediments—was ignored. A survey carried out by the vessel a week later found that the submarine cone had meanwhile collapsed and was now about 200 m below the ocean surface.

Civil protection measures taken in this 2011 submarine eruption in El Hierro (that posed little danger to human life) seem disproportionate and likely resulted from the lack of adequate scientific information.

This stresses the need to analyze such events to carefully, in order to improve the use of the scientific and human resources available during future events.
What would the outcome be if a volcanic eruption, instead of taking place off the small island of El Hierro, occurred in the densely populated islands of Tenerife or Gran Canaria?

Acknowledgements
This reconstruction of the 2011 submarine eruption in El Hierro, Canary Islands, is based in geophysical data obtained by the Spanish Geographic (IGN) and Oceanographic (IEO) Institutes. Carmen López and María José Blanco (IGN) provided valuable data and information.



Full article here: http://earthquake-report.com/2012/05...tion-overview/

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

Again, all Canarian seismographs have been off lines since yesterday morning 8 am.

No idea when the data will be all caught up on?

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

Again, CHIE and Tenerife (CCAN) seismographs have been off lines since yesterday 12 pm.

No idea when the data will be all caught up on?

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

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See top of page for the other auto-updating diagrams.

[Amzer Zo]

The La Gomera seismogram displaying the Italy and Honshu quakes:


---- MAG - UTC DATE-TIME ------ LAT ---- LON ---DEPTH ---- Region

MAP 6.0 2012/05/20 02:03:52 --44.800 - 11.192--- 5.1---- NORTHERN ITALY

MAP 6.4 2012/05/20 07:20:38-- 39.727- 143.037-- 15.6--- OFF THE EAST COAST OF HONSHU, JAPAN

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.

[Amzer Zo]

Strongest so far (no data):

For the day: :

Frequencies spectrogram, the vertical streaks indicate “events” (tremors/EQs) whereas the horizontal ones reflect volcanic/magmatic activity:

From Wikipedia: A Harmonic tremor is a sustained release of seismic and/or infrasonic energy typically associated with the underground movement of magma and/or venting of volcanic gases from magma. Being a long-duration continuous signal from a temporally extended source, a volcanic tremor contrasts distinctly with transient sources of seismic radiation, such as tremors that are typically associated with earthquake and explosion.

Refresh your browser page to get the latest traces.

See top of page for the other auto-updating diagrams.