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Interesting drilling job - Peter Harris - 20-Oct-2014 07:02 AM

[attachment=44]Came across this notice of a specialist drilling presentation: sounds interesting and challenging.

The Integrated Ocean Drilling Program (IODP) has embarked on an ambitious deep exploration project to drill a scientific borehole into the mega-splay of the Nankai Trough Subduction Zone located ~450 km SW of Tokyo, Japan. This international project (NanTroSEIZE) is the 1st attempt to drill, test, sample and instrument an active subduction plate boundary capable of generating M8+ earthquakes. The scientific objectives are to understand the physics of subduction earthquakes capable of generating massive tsunamis.

Twelve transect sites have been drilled across the trench axis, primarily for sampling, establishing a regional framework of observations and commissioning many wells for in-situ real-time monitoring. Several expeditions at one of these sites have occurred with the intent to drill a 7km vertical hole that intersects the stressed fault-splay. Expedition 348, ended in Jan 2014, after coming within 2.2 km of the mega-splay as planned.

We present a geomechanical postmortem of Exp 348 to explain the NPT encountered while drilling in this harsh environment and illustrate the process of using LWD and engineering information to design a forward well plan that delivers the borehole in a condition suitable for scientific observations in this all-important international project.


RE: Interesting drilling job - noel - 20-Oct-2014 11:31 AM

Fascinating study, though words like subduction earthquake need more than a bit of afterthought. What do you think of tracking, is it safe?


RE: Interesting drilling job - Peter Harris - 21-Oct-2014 01:53 AM

[attachment=45][attachment=46][attachment=47][attachment=45][attachment=46][attachment=47]It is fascinating, the subduction being the plate that goes under the other plate thus melting the ends into the liquid mantle below. This causes temperature, flow and pressure change in the liquid which causes cracking upwards in the plate above. You can get pictures showing the temperature variations at the edges as convection currents, and these line up directly with areas in which volcanoes etc form.

If anyone has ever been to Java in Indonesia you can see a perfect example of line after line of volcanoes following the subduction beneath.



The earthquakes are normally caused by friction as the two plates rub their rough edges together and slip.

Wouldn't like to be on top of the drilling derrick handling pipe into the elevators though if an earthquake happened below.


RE: Interesting drilling job - anacortesdamp - 21-Oct-2014 02:55 AM

We're on the eastern side of that zone, Peter, and there are fault lines all over the place in the Pacific just off our shore. We keep getting small earthquakes (Level 3 or less) along the fault lines. I'll be happy if they stay small and frequent, as we have four dormant volcanoes within 120 miles!


Frank


RE: Interesting drilling job - Peter Harris - 23-Oct-2014 01:50 AM

It was the same for us in Wellington Frank, the plate boundary goes through Wellington and we used to have several tremors every week, it was strange lying in bed and then the bed starts to sort of rotate under you.

This site monitors earthquakes and volcanic activity over there - see how many there are!

http://www.geonet.org.nz/


RE: Interesting drilling job - Fiverise - 23-Oct-2014 12:11 PM

Wow interesting site Peter, never realised that so many quakes were happening seems quite scary.


RE: Interesting drilling job - Dave H - 23-Oct-2014 02:50 PM

Same here on Crete, usually about well out out to sea but still moving the house enough, good job we are built on a seismic block, older property`s are not and cannot get earthquake insurance for their property. having said all that, earthquakes also happen in the British Isles.


RE: Interesting drilling job - anacortesdamp - 24-Oct-2014 02:46 AM

The "light quakes" in our area aren't usually enough to even wake us up, mainly Level 2 or less. The bigger quakes tend to be centered on the Greater Seattle area, from which we're about 100 miles north and a bit west.

We're more concerned about climate change. Our house sits on a lot with an elevation of 17 feet above mean high-tide sea level. The houses across the street are marina waterfront and 10' or so lower than ours. A 12' rise in sea level would increase our house value by about 200%, since the houses between us and the marina would have been destroyed and we'd be waterfront! Won't happen in our lifetime or even that of our not yet born great-grand-kids, but it's an interesting take on the "value of investment".


Frank


RE: Interesting drilling job - sandyship - 28-Oct-2014 07:19 AM

(24-Oct-2014 02:46 AM)anacortesdamp Wrote:  The "light quakes" in our area aren't usually enough to even wake us up, mainly Level 2 or less. The bigger quakes tend to be centered on the Greater Seattle area, from which we're about 100 miles north and a bit west.

We're more concerned about climate change. Our house sits on a lot with an elevation of 17 feet above mean high-tide sea level. The houses across the street are marina waterfront and 10' or so lower than ours. A 12' rise in sea level would increase our house value by about 200%, since the houses between us and the marina would have been destroyed and we'd be waterfront! Won't happen in our lifetime or even that of our not yet born great-grand-kids, but it's an interesting take on the "value of investment".


Frank

(28-Oct-2014 07:19 AM)sandyship Wrote:  We in Nz have had major quakes over the last 4 years . In August 2013 I was in school teaching when a 6.4 hit us. very scary. did major damage and lots of aftershocks. we all have emergency kits at home. Blenheim lies on a major fault line and have always been waiting for the big one. Wellington got shaken by this one also. They are scary but you sort of get used to the shakes,



(24-Oct-2014 02:46 AM)anacortesdamp Wrote:  The "light quakes" in our area aren't usually enough to even wake us up, mainly Level 2 or less. The bigger quakes tend to be centered on the Greater Seattle area, from which we're about 100 miles north and a bit west.

We're more concerned about climate change. Our house sits on a lot with an elevation of 17 feet above mean high-tide sea level. The houses across the street are marina waterfront and 10' or so lower than ours. A 12' rise in sea level would increase our house value by about 200%, since the houses between us and the marina would have been destroyed and we'd be waterfront! Won't happen in our lifetime or even that of our not yet born great-grand-kids, but it's an interesting take on the "value of investment".


Frank



RE: Interesting drilling job - Peter Harris - 31-Oct-2015 09:31 AM

The Te Papa museum in Wellington has a marvellous earthquake simulator room inside. Very realistic. All the loose stuf thrown around and all that .........