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Tom Blake – RTE Morning Ireland Broadcast

Tom Blake’s interview for RTE Morning Ireland. Listen to it HERE.

2017-8-10 – Seminar by Prof. Balz Kamber (TCD)

10 August 2017Seminar

When: 16:00 on Thursday, 10th August 2017
Where: DIAS, Geophysics Section, 5 Merrion Square, Dublin 2, (library)

Speaker: Prof. Balz Kamber (Department of Geology, Trinity College Dublin)
Title: Why Archaean cratons differ from younger continental lithosphere.

Abstract:

The most outstanding features of Archaean cratons are their extraordinary thickness and enduring longevity. Seismically, Archaean cratonic fragments are sharply-bounded deep roots of buoyant cold lithospheric mantle, clearly distinguishable from non-cratonic lithosphere. The age of diamond inclusions and the Os-isotope composition of deep cratonic xenoliths support a model of coeval formation of the crustal and residual mantle portions.
Archaean and post-Archaean crust also differ, not in bulk composition, but in crustal architecture. Key drivers of crustal rearrangment were the radioactive heat-producers U, Th and K. In the early Earth, high radioactive heat production led to self-organisation into evolved, potassic upper and refractory lower crust. The lag time between crust formation and re-organisation was much shorter than today. An additional factor contributing to cratonic restruc-turing was the emplacement of dense supracrustal rocks in ensialic greenstone belts, leading to gravitational inversion. The dome and keel architecture of Archaean cratons was thus driven by crustal radioactive heat and high temperature mantle melting, yielding dense, low viscosity lavas piling up at surface.
A pleasing complementary observation from cratonic mantle roots is that refractory mantle nodules also suggest very high degrees of melting and extraction. Thus, the most logical conclusion seems that the komatiite mantle source was up to 500ºC hotter than modern astheno¬sphere. With higher degree and depth of melting, a thicker and severely depleted bouyant cratonic residue was formed, perfectly equipped to preserve the Archaean crustal record.
However, there are significant inconsistencies in this otherwise convincing line of reasoning. They include: Archaean crust is not especially thick, the dunites expected after very high degree melting are rare, many cratonic harzburgites are much richer in orthopyroxene than predicted [1], and cratonic harzburgites often contain garnet. Finding a solution to these issues has important ramifications for secular evolution of the continents and thermal evolution of the mantle. In this presentation, I will contrast the various proposed solutions, including purging of surprisingly carbonated ancient mantle [e.g. 2], onset of plate tectonics, a Neoarchaean superplume event and collapse of Hadean cumulate barriers.
[1] Boyd (1989) EPSL 89, 15-26
[2] Herzberg (2016) J. Petrol. 57, 2271-2288

Earthquake Donegal, 2nd August 2017, M1.5

On the 2nd August at 05:46 UTC (06:46 local time) an earthquake of magnitude 1.5 occurred in Donegal (NE of Milford on the Fanad Peninsula). Location 55.11N, 7.59W, see figure below.

There are reports of this event having been felt in the area around Milford. Events of this nature are not uncommon in this region. The largest event recorded in this area was a magnitude 2.2 which occurred near Clonmany on 21st November 1994.

The event was recorded at stations of the Irish National Seismic Network (INSN) and the BGS, see seismic traces below.

Sediments make the colour: Dr. Eva Eibl’s photo/post on EGU Blogs

Imaggeo on Mondays: Sediments make the colour! Read Eva’s piece on EGU Blogs

Imaggeo on Mondays: Sediments make the colour

2017-06-02 – Agallamh le Blas ar BBC Raidió Uladh BBC Gaeilge T Blake interview

2nd of June 2017 – Interview for the BBC Radio Ulster – Thomas Blake, the Director of Observational Seismology at the Dublin Institute for Advanced Studies speaks about the strength of Irish earthquakes and their regularity.

Listen to this interview here: http://www.bbc.co.uk/programmes/p054r7r3

2017-05-18, Earthquake in Irish Sea, M1.3

An earthquake with magnitude ML 1.3 occurred on the 18th May 2017 at 23:04:12 UTC in the Irish Sea. The epicentral location of this event is 53.05N, 5.49 W, about 40km off the Wicklow coast, see map below.

The earthquake was detected by seismic stations of the Irish National Seismic Network (INSN) and the British Geological Survey (BGS), see seismograms below.

The epicentre is close to the location where a similar earthquake with magnitude ML 0.9 occurred on the 10th March 2017, see here for more information. Real-time information of automatic INSN event detections can be accessed  on the INSN homepage at https://www.insn.ie/events.

Andrea Licciardi wins outstanding Student presentation at EGU 2017

During the Geodynamics division meeting at the 2017 EGU general assembly, that took place in Vienna on April 25, DIAS former PhD-student, Andrea Licciardi has been awarded with the Outstanding Student Presentation and Pico (OSPP award). Andrea presented new evidence about crustal anisotropy along the North-Anatolian Fault system obtained using passive seismic observations. This study is a joint collaboration between DIAS, GFZ and Istanbul Technical University. His poster was titled: “Crustal anisotropy along the North Anatolian Fault Zone from receiver functions”

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DIAS Research Forum 2017 – Wednesday 17th May

 

An inter-disciplinary research forum has been scheduled for Wednesday 17 May 2017, 3-5pm at Burlington Road. The forum is intended to be an informal event that provides post-doctoral scholars and PhD students with the opportunity to share and discuss their current research with scholars and staff from across the three schools of DIAS.

There will be no main speakers at the event. Instead, participants will be assigned a space where they can share and discuss their research interests. Participants are encouraged to present a poster which visually complements their research, and allows them to explain what they do to all DIAS staff. In instances where a poster presentation is not appropriate, participants should feel free to develop an alternative approach.

The forum presents a great opportunity for scholars to sharpen their academic presentation and public outreach skills in an informal setting, while also getting to know colleagues from across the Institute.

The organisers strongly encourage scholars from all three schools to participate in the forum. A coordinator from each section will liaise with participants regarding their presentations.

Participants are asked to register here prior to Friday 12 May.

Section Coordinators:
Celtic Studies - Eibhlín Nic Dhonncha eibhlin@celt.dias.ie
CP, Astrophysics - Eileen Flood eflood@cp.dias.ie & Anne Grace ag@cp.dias.ie
CP, Geophysics - Clare Horan choran@cp.dias.ie
Theoretical Physics - George Rogers grogers@stp.dias.ie
Please contact your section coordinator with any queries.

All DIAS staff are welcome to attend.

 

2017-4-10 – Seminar by Prof. Tarje Nissen-Meyer

10 April 2017Seminar

When: 16:00 on Monday, 10th April 2017
Where: DIAS, Geophysics Section, 5 Merrion Square, Dublin 2, (library)

Speaker: Prof. Tarje Nissen-Meyer
Title: Occam or not? On the interaction of waves with structure.

2017-4-5 – Seminar by Prof. Heiner Igel

5 April 2017Seminar

When: 16:00 on Wednesday, 5th April 2017
Where: DIAS, Geophysics Section, 5 Merrion Square, Dublin 2, (library)

Speaker: Prof. Heiner Igel (Ludwig-Maximilians-University München, Germany)
Title: Earth’s Rock and Roll: Rotational Motions in Seismology.