GeoLog

Tectonics and Structural Geology

Imaggeo on Mondays: An explosive cloud

Imaggeo on Mondays: An explosive cloud

One of the world’s most volcanically active regions is the Kamchatka Peninsula in eastern Russia. It is the subduction of the Pacific Plate under the Okhotsk microplate (belonging to the large North America Plate) which drives the volcanic and seismic hazard in this remote area. The surface expression of the subduction zone is the 2100 km long Kuril-Kamchatka volcanic arc: a chain of volcanic islands and mountains which form as a result of the sinking of a tectonic plate beneath another.  The arc extends from Hokkaido in Japan, across the Kamchatka Peninsula, through to the Commander Islands (Russia) to the Northwest. It is estimated that the Pacific Plate is moving towards the Okhotsk microplate at a rate of approximately 79mm per year, with variations in speed along the arc.

There are over 100 active volcanoes along the arc. Eruptions began during the late Pleistocene, some 126,000 years ago at a time when mammoths still roamed the vast northern frozen landscapes and the first modern humans walked the Earth.

Many of the volcanoes in the region continue to be active today. Amongst them is Karymsky volcano, the focus of this week’s Imaggeo on Mondays image. Towering in excess of 1500 m above sea level (a.s.l), the volcano is composed of layers of hardened lava and the deposits of scorching and fast moving clouds of volcanic debris knows as pyroclastic flows. You can see some careering down the flanks of the volcano in this image of the July 2004 eruption. The eruptive column is the result of a

“strong Vulcanian-type explosion, with the cloud quickly rising more than 1 km above the vent. The final height of the eruption cloud was approximately 3 km and in the image you can clearly see massive ballistic fallout from multiple hot avalanches on the volcanoes slopes,”

explains Alexander Belousov, a Senior Researcher at the Institute of Volcanology and Seismology in Russia and author of this week’s photograph.

 

USGS map of the Kuril-Kamchatka trench, showing earthquake locations and depth contours on downgoing slab. Credit: USGS, USGS summary of the 2013 Sea of Okhotsk earthquake, via Wikimedia Commons.

USGS map of the Kuril-Kamchatka trench, showing earthquake locations and depth contours on downgoing slab. Credit: USGS, USGS summary of the 2013 Sea of Okhotsk earthquake, via Wikimedia Commons.

If you pre-register for the 2015 General Assembly (Vienna, 12 – 17 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

Imaggeo on Mondays: Landslide on the Cantabrian coastline

Shimmering blue seas, rocky outcrops and lush green hills sides; this idyllic landscape is punctuated by a stark reminder that geohazards are all around us. Irene Pérez Cáceres, a PhD student at the University of Granada (Spain) explains the geomorphology behind this small scale landslide on the Asturian coastline.

Landslide on the Cantabrian Sea. Credit: Irene Pérez Cáceres (distributed via imaggeo.egu.eu)

Landslide on the Cantabrian Sea. Credit: Irene Pérez Cáceres (distributed via imaggeo.egu.eu)

This picture was taken in May 2011 in the coast of Llanes (Asturias, Spain). I was living in Oviedo (Asturias, Spain) doing my Master in the structural geology of the Axial Zone of the Pyrenees. Thus, geomorphology and geohazards are not my specialty or area of expertise. However, the landslides are well known and studied in this region, and people from Asturias call them Argayos.

This argayo is situated in Niembru Mountain, over the San Antolín beach, constantly affected by waves and swell of tides of the Cantabrian Sea, and continuous rain typical in the region. It was defined as a rotational landslide with two fracture surfaces, possibly conjugated in wedge shape. It is approximately 50 meters high and 60 meters width at its base. The slide volume is calculated at 45000 m3. It is carved in quartzite altered by the water rain infiltration through crevices in the surface. The initial displacement was between 10 and 15 meters in the scar. Experts say this landslide is still active, moving and evolving continuously. It is an imminent risk for the swimmers, but it is very difficult to control it, due to the size and the slope, and the technical requirements to stabilize the rock. On the other side of this mountain, further landslides are evident, as a result of the building of a road.

These natural geomorphological processes are very common in the north of Spain, mainly in riverbeds, as well in other nearby beaches. The main causes are the abundant (and sometimes heavy) rainfall, the typically clay rich soils, steep slopes, building works that destabilize the slopes, and the absence of vegetation in some areas. They vary in in size and volume, and can sometimes have important material consequences and can pose a significant risk for the local inhabitants. The annual economic cost for repairing the damage caused by these processes is estimated to be 66 million of euros in this region.

Studies carried out in the Department of Geology of the University of Oviedo (Mª José Domínguez and her group), indicate that 70% of the landslides in Asturias happen when it rains over 200 mm during over a period of a minimum of three days. Research has also been carried out to try and predict when landslides might happen, examining numerous landslides over the last 20 years approximately. It seems that one conditioning factor is the exact location of new buildings, being that ancient constructions used to be in secure zones, probably because people observed more minutely to the nature, but the new ones are more vulnerable.

To conclude, detailed geological and geomorphological studies are always recommended to carry out before constructions. Thereby it is possible to minimise this common geohazard in Asturias.

By Irene Pérez Cáceres, PhD Student, Granada University.

 

If you pre-register for the 2015 General Assembly (Vienna, 12 – 17 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

GeoEd: A risky business

In this month’s GeoEd post, Sam Illingworth explores the pitfalls of being a scientist in the public eye. Following the recent acquittal of 6 geoscientists on manslaughter charges after ‘failing’ to predict the 2009 L’Aquila earthquake, is it time we thought about improving how risk is communicated to the wider public?

At the beginning of November of this year, six Italian scientists were acquitted of manslaughter; an appeals court in L’Aquila (a medieval Italian city on the edge of the Aterno river) overturning the 2012 guilty verdicts that were originally cast against the researchers.

In their initial trial, the scientists were convicted of multiple manslaughter charges, by failing to predict the devastating earthquake, which struck at 03:32 CEST on 6 April 2009, and which was responsible for the deaths of 309 people. It has taken the past two years to acquit these six scientists, and the initial ramifications of the convictions were far reaching, with other researchers from across the globe wondering if a precedent had now been set, regarding liability for the conveyance of information.

Aerial view of the city of L'Aquila east-centre (Photo Credit: Public Domain, via Wikipedia.org)

Aerial view of the city of L’Aquila east-centre (Photo Credit: Public Domain, via Wikipedia.org)

Sadly, scientists are far from unaccustomed with judicial proceedings, from Galileo vs. the Catholic Church, to more recent examples of scientists being sued by a gym regarding injury rate statistics, or NASA being sued for trespassing on MARS. However, the recent allegations against the L’Aquila six (actually there were seven experts in total; more on this later), calls into question the fundamental belief system of accountability. If a building surveyor were to tell you that the foundations of your house were sound, yet you were later to find evidence of subsidence you would expect compensation from the surveyor. So why not also from the scientists, after all are they not too experts in their own field?

Well, for one thing, finding evidence for subsidence is far more of a precise art than trying to predict earthquakes. On the one hand you are looking for something that already exists, and on the other you are searching for something that may or may not be. In addition to this, surveyors are usually protected by professional indemnity insurance.

Are scientists adequately protected (Photo Credit: Sandstein via Wikimedia Commons)

Are scientists adequately protected (Photo Credit: Sandstein via Wikimedia Commons)

However, in the case of scientists communicating risk, is not being able to accurately predict an earthquake or a volcanic eruption really professional negligence, or is it simply to be expected given the impossibility of fully accurate predictions?

What is potentially worrying to scientists is that the line between professional negligence and unforeseen circumstance would appear to be very blurred indeed. Although, in some instances the distinction is far more clear-cut, for example the behaviour of the seventh member of the panel of experts in the L’Aquila case, Bernardo De Bernardinis. The then deputy director of the Civil Protection agency had, prior to the earthquake, advised locals to “sit back and enjoy a nice glass of Montepulciano” wine. Bernandinis was not acquitted, although his prison sentence was cut, from six to two years.

Although many might view Bernandinis as being guilty of nothing more than pompous over confidence, it is important to remember that as scientists we still have a role to inform the public as to the seriousness of any potential dangers, even if we are not ultimately to be held accountable for our inability to predict them. In other words, failing to predict a natural hazard (or other such incident) should not be seen as professional negligence, but failing to adequately inform the general public of the consequences of any potential threats, probably should be.

Of course, communicating risk goes well beyond natural disasters, and is something that many of us do when we talk about the effects of both current and predicted climate change. In these situations, scientists also regularly put themselves in the firing line, although this time often with regards to the media and pressure groups with an anti-climate change agenda.

One of the most well known examples of this was when a Competitive Enterprise Institute (CEI) analyst made the following, frankly horrific statement, about Penn State University climate researcher Michael Mann:

“Mann could be said to be the Jerry Sandusky of climate science, except that instead of molesting children, he has molested and tortured data in the service of politicized science.”

Dr Michael Mann: fighting the fakers (Photo Credit: Reason4Reason via Wikimedia Commons)

Dr Michael Mann: fighting the fakers (Photo Credit: Reason4Reason via Wikimedia Commons)

Dr Mann has subsequently sued the CEI, but such legal proceedings are both incredibly expensive and time consuming, and often represent a completely alien world to many scientists who are simply just doing their job.

In the US, scientists working for government or federal labs are now offered free legal counsel and support by the organization Protecting Our Employees Who Protect Our Environment (PEER). In addition to this, some scientific professions are now requiring their researchers to have professional indemnity insurance, for example in the UK, legislation was recently introduced that requires all health care scientists to have a professional indemnity arrangement in place, as a condition of their registration with the health & care professions council.

According to Jeff Ruch, the director of PEER, threatening scientists for their science “is a bully strategy,” and “bullies don’t like to be pushed back at.” Whilst the work of PEER and their contemporaries is admirable, is this a position that scientists should ever be finding themselves in? And is there anything that they could be doing to avoid such potential pitfalls?

In some cases, these pitfalls could be avoided by a more careful consideration of how to communicate risk, by explaining to the general public that there are many uncertainties associated with the calculations and predictions that are being made. However, I think that this is something that many scientists are already reasonably adept at, and if scientists are guilty of anything it is sometimes of being overcautious with their predictions, or of waiting to comment until they are absolutely 99.9% sure (with the obligatory 0.1% margin of error).

Media and science communication training can help scientists prepare for how to deliver their research and advice in potentially alien and hostile arenas, but there will always be instances where people have a set agenda to follow at any cost.

There may well be a public perception that scientists failing to predict natural disasters, or underdetermining a certain problem, are like the proverbial bad workmen who blame their tools. However, in trying to communicate risk I think that it might well be a case of “don’t shoot the messenger,” even if it turns out that they have no message to convey.

By Sam Illingworth, Lecturer, Manchester Metropolitan University

 

GeoTalk: Stacia Gordon

Geotalk is a regular feature highlighting early career researchers and their work. Following the EGU General Assembly, we spoke to Stacia Gordon, the winner of the Tectonics and Structural Geology Division Outstanding Young Scientist Award, 2014.

Meet Stacia! (Credit: Stacia M. Gordon)

Meet Stacia! (Credit: Stacia M. Gordon)

First, could you introduce yourself and tell us a little more about your career path so far?

My name is Stacia Gordon. I am an Assistant Professor at the University of Nevada, Reno (UNR). This fall marks the start of my fifth year at UNR. It is amazing how fast the time has gone by! As an assistant professor, I quickly learned that being successful means being a good juggler and having good time management, as there are so many things that require attendance on a day to day basis…..graduate students, undergraduate students, manuscripts, data reduction, teaching, proposals, service work, etc. Prior to UNR, I had many amazing mentors that helped teach me how to manage all of these tasks that are required of you as a professor. Before I moved to UNR, I spent a semester at the Lamont-Doherty Earth Observatory (LDEO) under the Marie Tharp Fellowship, working with Dr. Peter Kelemen. This was an excellent opportunity to collaborate with a great scientist and meet and interact with many other scientists through the numerous seminars that occur every week at LDEO. LDEO also has the most well-organized intramural sports activities of any Earth Science department. Thus, I thoroughly enjoyed taking a break from science to go play soccer during the week.

I also had an excellent mentor during my postdoctoral research at the University of California-Santa Barbara, working with Dr. Brad Hacker. I think I spent nearly half of the postdoc away from UCSB, traveling for meetings, fieldwork, and lab work, but I learned a large amount of science and various writing tips for submitting a successful proposal from Brad. Brad also introduced me to many new collaborators (most notably Tim Little, Laura Wallace, and Susan Ellis). In addition, spending free time in Santa Barbara is not too shabby, with its lovely combination of ocean and mountains.

My real passion for understanding the mid- to lower-crust began during my dissertation work, while studying under Drs. Donna Whitney and Christian Teyssier at the University of Minnesota. I owe a tremendous amount of gratitude to Donna and Christian and am very happy that I continue to collaborate with them today. In addition, the STAMP (structure, tectonics and metamorphic petrology) group at the U always provided a support network of individuals in which to bounce ideas off of, ask questions, have a beer with, etc. Finally, my dissertation project also introduced me to Bob Miller and Sam Bowring. Both of whom I continue to collaborate with today, and they both had a great influence on my upbringing as a geoscientist. While it was extremely cold living during the winters in Minnesota, the Twin Cities and Pillsbury Hall (where the geology department is housed) were always warm, welcoming places.

 

During EGU 2014, you received a Division Outstanding Young Scientists Award for your work on integration of microstructural data with geochronology, metamorphic petrology, and geochemistry. Could you tell us a bit more about your research in this area?

I am very interested in understanding the thermal, chemical and rheologic changes that occur during orogenesis, and specifically understanding the interaction and timing among processes, such as metamorphism, deformation, and partial melting. I have been working on these processes in a variety of tectonic environments, from ultrahigh-pressure terranes (Papua New Guinea, the Western Gneiss Region of Norway) to regions where mid- to lower-crustal rocks are exhumed (North Cascades of Washington, eastern Bhutan in Bhutan). I use a combination of field and laboratory work, including various types of geochronology (high-spatial resolution techniques: ion microprobe and laser-ablation inductively coupled plasma mass spectrometry (ICPMS); and high-precision technique: thermal ionization mass spectrometry), ICPMS trace-element analyses, ion microprobe oxygen-isotope analyses, EMPA chemical analyses. These tools allow me to decipher the pressure-temperature-deformation-time path that the rocks underwent within these terranes. Knowing how and when the rocks were deforming and the maximum depths that the rocks reached allows geoscientists to better understand the processes that led to the burial and the exhumation of mid- to lower-crustal rocks. This also contributes to understanding how mountain belts grow and evolve through time, from when the crustal is thickening to when the mountain belt undergoes collapse and extends, falling apart.

 

What sparked your interest in tectonic processes and what inspired you to use the innovative approach, for which you’ve been recognised, to better understand mountain building and subduction?

This may sound a bit cliché but my interest in tectonic processes began as a child. I was raised in the mid-west of the United States, which has been heavily glaciated and is thus the topography is flat. My family would take vacations to the Western United States where I would see the Rocky Mountains and the Cordillera, both significant orogenic belts. As I child, I wondered why some areas were flat and others mountainous. I decided when I reached the University to take a geology class. After taking Geology 101, an introduction geology class, I specifically became interested in hard-rock geology. I found it fascinating that rocks of the mid- to lower-crust have reached high-enough temperatures to ductilely flow, and I was very interested in understanding how orogenic belts rest upon this very weak, ductilely flowing base. In addition, I was (and still am) fascinated that parts of the crust are taken, via subduction, to mantle depths and are brought back to the surface. My undergraduate research advisor was working on some of these high-pressure rocks exposed in Poland, and I was able to do a small project with him on these rocks. Thus, by the end of my undergraduate education, my interest in hard-rock geology was well developed.

Stacia in  Bhutan. (Credit: Stacia M. Gordon)

Stacia in Bhutan. (Credit: Stacia M. Gordon)

At the General Assembly in 2014 you gave an oral presentation about the findings of your research on the Western Gneiss Region, Norway. Could you tells more about the key findings you presented there?

I have been working in the Western Gneiss Region (WGR) since my postdoc. Brad Hacker introduced me to these incredible rocks, and since this time, Donna Whitney, Christian Teyssier, Haakon Fossen and I have been collaborating, with students, on various parts of the WGR. Within this terrane, it is divided into an ultrahigh-pressure portion (i.e., rocks that were exhumed from mantle depths) and a portion that appears to have also undergone high pressures but that also achieved high-temperature conditions. Within both of these portions of the WGR, there are mafic rocks that are hosted by migmatitic gneisses that underwent partial melting. We have been studying the partial melting history for the WGR because when melt is present, it will be very buoyant. This buoyancy may help exhume rocks from mantle depths. In addition, a small percentage of melt (~7%) will drastically decrease the strength of the rocks; therefore, the melt will play a significant role in how the mountain belt is deforming through time. I have dated numerous of the now crystallized melt bodies and have found that many of the dates that record the timing of melting overlap in time with when the mafic rocks were undergoing metamorphism in the mantle. Thus, this suggests and supports field and experimental evidence from other studies/investigators that partial melting began at mantle depths and may have triggered the switch from the mafic rocks residing in the mantle to being exhumed toward Earth’s surface.

In addition, as mentioned above, we have analysed samples from both portions of the WGR, and we find that the timing of the partial melting is consistent across the entire WGR. This represents a significant portion of the central-western coast of Norway shared the same melting history and thus implies that melting was ubiquitous at the end stages of this mountain building event and likely helped to drive the exhumation of these high-grade rocks back to the surface.

 

Generally speaking, what are the main challenges when trying to understand the processes that govern burial and exhumation of rocks?

Probably the hardest part about trying to understand these processes is being able to decipher the different parts of the burial and exhumation history. The laboratory tools that I use to understand the pressure-temperature-deformation-time path uses the chemistry of the minerals found in metamorphic rocks. The chemistry of these minerals can preserve a record of multiple thermal events that have occurred over time, and this allows geoscientists to understand both the burial and exhumation history. However, in some cases, the earlier history can become overprinted or erased so that it is difficult to know what happened prior to the exhumation history of the rocks. I would say this is one of the biggest challenges in understanding these challenging rocks.

Field work in Bhutan. (Credit: Stacia M. Gordon)

Field work in Bhutan. (Credit: Stacia M. Gordon)

 

During field work there are highs and lows, and as your research has taken you to some pretty interesting localities, (Bhutan, Norway, Papua New Guinea) no doubt you’ve had some memorable field work moments whilst at the same time overcoming some tough challenges. Can you tell us more about your field work highs and lows?

The overall high for pretty much all of the places I have worked (besides the rocks) is the scenery: all of these countries are beautiful places. Also, high in the list is the opportunity to meet with local people and see lots of different cultures. Many of these places (e.g., Papua New Guinea and Tajikistan) I would likely have not travelled to as a tourist so I have really enjoyed being able to go there for the geology. In particular, when traveling to countries as a geologist, you likely get off the beaten path very quickly and so I think it is a view of many places that a typical tourist does not see.

There are definitely challenges to working in a variety of these places. In many of the foreign localities, there is a significant communication barrier, where I don’t speak the local language, but we have found some locals who speak English to help with the field work. However, commonly, their English is weak so there is constantly miscommunication about what we want to do, which means that there are constantly evolving plans. This can be very frustrating as typically we want to target very specific rocks that are exposed in very specific geographic locations. It is not until we are in the country that we find out that it is not possible to get to a particular location, which after planning for a trip for multiple months before the field work, can be maddening.

Papua New Guinea (PNG) has definitely been one of the most amazing places to work but also the most frustrating. Most of the people are very kind, but there are also many that assume that as a foreigner from the United States that you have lots of money and are trying to exploit the locals in some way. Thus, we spent many a hours talking to people, explaining what we were doing and trying to get permission to work our way up rivers (where the rocks are exposed). In some cases, the locals would either flat out refuse our request to go up the river or would want a significant amount of money meaning that we would have to turn around and give up on a certain trek. On my two trips to PNG, however, we worked with some fantastic local guides that led us up the rivers. The rocks in the rivers were very slippery, and we would easily fall multiple times throughout the day. The local guides, however, would never slip, carried our heavy back packs, and did it all barefoot! They had the most incredible balance and were extremely savvy with using the local jungle to produce whatever they would need in that moment. For example, at one point, we came to a waterfall that we could not scale. Within 15 minutes, our guides had cut down trees, found vines to use as rope, and built us a ladder to go up and over the waterfall! There were multiple incidents like this that we foreigners would watch in awe!

Field work is definitely one of my favourite parts of the job. I don’t have to sit at a desk all day but instead, get to hike around beautiful mountains. Thus, there definitely many more highs than lows that I have found in all of the places I have worked.

Finally, what does the future hold for you in terms of your research and career plans?

I would like to continue working on some of my current research interests but look forward to developing new skills, investigating new research avenues, mentoring many new graduate students, and collaborating with many new individuals! What I have learned from being a Geoscientist thus far is that there are many questions still to be answered about Earth and that as one researches a topic or chats with a colleague, that new research ideas quickly form.

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