Ongoing Effusive Activity: 🌋 5 Years VH 🌋

Is it really 5 years…? Indeed! Background image: Announcement for our new VH blog in February 2015. Logo pinched from… um… the Indeed Brewing Company)

We find that our blog has been alive, growing and changing for 5 years, which has surprised us, as we didn’t think it was that long. Many, many thanks to you, our readers, for your loyalty, your interest, support and comments.

Hokkaido 2 – The Mashu Caldera, Hokkaido, Japan

Mashu caldera in winter with Kamuinupuri to the right of the photo and the Kamuishu dome in the middle of the lake. Image courtesy Wiki

 

The Toya – Usu post led me to the interesting volcanic history of Hokkaido, Japan.  Found a multiple caldera complex in eastern Hokkaido with three calderas in close proximity to one another.  Will write about these for the next few posts.

TUFF.. TUFA?.. IGNIMBRITE – Pyroclastic Deposits

Erosional structures at Göreme, central Cappadocia Region. The tuff is thought to have been deposited by the Mount Erciyes eruption ~2.6 ma, covering an area of about 20,000 km². This was the last of the series of great Cappadocian ignimbrites. (© Claude Valette, via Wikimedia)

In many descriptions of volcanoes and their eruption histories we stumble upon the terms Tuff, Tufa or Ignimbrite. Most every self-respecting volcano has one or all of them. Generally it becomes obvious from the context that they refer to widespread deposits of volcanic materials. But what exactly is an ignimbrite?, is it different to tuff?, and where do they all come from?

Tuff and ignimbrite are clastic rocks composed of volcanic

What is an Intraplate Earthquake?

Schematic of location of Nov 30 Anchorage earthquake. Image courtesy Temblor.net

 

Intro:  I wrote this some 12 months ago, a couple months after our M7.1 intraplate earthquake here in Anchorage.  This seems a good time to revisit what happened and why.  As usual, there are more questions afterwards than before.  Cheers –

VOLCANO ARMCHAIR HIKING – A Christmas Special

Fujisan

You may be about 90 and no longer able to travel the volcanoes of the world; you may be a young student lacking the funds as well as the friends willing to climb your favourite volcano with you; you may be an inveterate couch potato, or, you just want to spend some relaxing armchair time during the holiday season – don’t despair!

Sent Ash Around the World – Volcán CEBORUCO, Mexico

View from Los Aguajes in the east of Volcán Ceboruco. (© Juan Castillo Campos, via mapio.net)

As so often, and generally without intention, I have hit upon yet another volcano that has all the trimmings of a beast but seems not really to be recognised as such. Up to a few years ago there have been very few studies to find out about the seismological and structural properties of the volcano. Volcán Ceboruco is considered among the five volcanoes with the highest risk in Mexico, and the second most active after Colima volcano in the western Trans-Mexican Volcanic Belt. Yet, scientists had to point out, in a 2016 study, “that every effort should be made to monitor its seismic activity”.

Volcanoes of Io – Part 2 – The Volcanoes

Galileo 1998 image of Io. This one shows two active plumes. Pillan Patera plume is at the upper limb of the moon. It is 140 km tall. Second active plume is Prometheus Patera center bottom near the terminator between dark and light

Volcanoes of Io – Part 1 – Introduction

Io. Orange is plume deposit around Pele Patera. Multiple patera and plains are visible. Note lack of impact craters meaning the moon is regularly resurfaced. Image courtesy NASA JPL via Sen.com

Volcanoes where we don’t expect them – GARROTXA VOLCANIC FIELD, NE Spain

Castellfollit de la Roca: The confluence of the rivers Fluvià and Toronell created this stunning geological monument between them: a 1 km long and 50 m high basaltic lava crag, consisting of two superimposed lava flows with columnar jointing. (© Nasobema lyricum 2006, via Wikimedia)

View to the north over the northern part of Garrotxa VF, with the town of Olot in the left middleground. In the background the snow covered Pyrenees can be seen. (© turismegarrotxa.com)

Today our fancy takes us to the NE of Spain. Just to the corner where the Pyrenees mountain range meets the Mediterranean Sea, to the province of Girona in Catalonia. For millions of us European tourists the Mediterranean Costa Brava with its golden beaches is a household name. As in so many other touristic spots in the world, one could ask, how many of the sun worshippers would have known that, some 60 km inland, there is a volcanic field to be visited?

Makushin Volcano, Alaska. The 9th Most Dangerous Volcano in the US?

Active fumaroles on Makushin Volcano from Dutch Harbor July 2018. Photo courtesy Abi Woodbridge, via AVO