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Jun 24, 2013

Project Heracles: The Field Work, Part I



Field work, Day 1, was mostly spent unpacking the car, setting up and organizing the field office, establishing the survey base, and disassembling the first batch of seismic stations that had been recording since last September. Then it was off to the supermarket for basic supplies such as 2 liter bottles of water, sandwich making material, tomatoes, cucumbers, retsina, and ouzo. The absolute basics.

Days 2 and 3 were mostly spent in that nasty form of field limbo that geophysicists are sent to when things don't work: waiting for permits, endless discussions about why things don't work, and making trips to get parts and odds and ends. But despite the threat of rain, we made our first passive seismic measurements in Midea. Hurrah!
 
Klaus, Gregor, Hector and Evi leveling seismometers in Midea
  
Evi measuring a GPS location on a rock in Tiryns (they're digging in the wrong place, Indie!)
 Another important accomplishment was checking the extent of our new differential GPS in preparation for measuring a gravity profile extending all the way from Tiryns to Midea. Measuring gravity requires precise locations, especially elevation, because gravitational anomalies – those are the interesting things – can only be well modeled if the single points that are measured with a gravimeter are well known. The tidal corrections, elevation corrections, geoid corrections, etc. and so on, all depend on the accuracy of the locations. We are using a Scintrex CG-5 gravimeter that our Belgian colleagues Michel von Camp and Thierry Camelbeeck at the Royal Observatory in Brussels haven generously lent us for the experiments.

While doing our base station tests, we stopped near the house where we had installed a seismometer last year. The nice Greek grandmother who owns the house saw us and made us come inside where she plied us with cucumbers (from her garden), melons (from the neighbor's garden) and fresh well water. I wouldn't have understood a word of her non-stop exuberant conversation if it hadn't been for our versatile and multi-talented geophysicist helper Evi Seferou. Evi kept up a simultaneous translation of Grandma's speech which alternated between exhortations (Eat! Eat! You are all too thin!) and stories about her children, her garden, and whether we wanted to stay the night and keep her company. We brought her cookies the next day, and she yelled even more loudly over the fence and gave us more cucumbers to take home.
 
A very nice Greek grandmother. Part of me wanted to take her home with us.
 Day 4 was also mostly spent in discussions – it seems that the Greeks are very keen on this. Then after all the tiniest details had been covered, we began to clear the East Gallery in Tiryns in preparation for the 3D laser scanning. It was rank under-gardener work with an industrial weed cutter and hand-pulling dried grasses and the occasional Spritzgurke. Science at its least glamorous. These are the pictures they don't show you in the BBC or Nova presentations about how science works.

Under-gardening on a Mycenaean ruin

Friends for life - Gregor and an industrial-strength weedeater.
 Saturday, we worked until late afternoon – first measuring the gravity along the windy road leading up the slope to the acropolis of Midea. We were only seriously interrupted once by a goat-herding Greek grandmother (the second grandmother in a series of four). She wanted us to move the car because the goats wouldn't go past it. Superstitious goats? Not fond of French cars (Citroen)? She screamed at us (and not the goats) but did not offer us either cucumbers or melons. Her daughter came with a stick and length of thick rubber hose to encourage the goats to follow her. The hose made a low frequency noise as she dragged it behind her that enticed the goats. 

Goat and grandmother
 Evi told me that all the small landholders here have goats or sheep, a few olive or orange trees and impressive gardens (for cucumbers and melons). The government pays a small amount per annum to promote the continuance of the local farming economy. It's not enough to live on. Most of the farmers produce enough for their own use but not much more. 

The road goes ever on and on - the windy drive leading to ancient Midea, for example
Just call me the human raisin because that's what I'll be after another week in the Greek countryside with average temperatures around midday of 34o C in the shade. The east European heat wave is holding strong (probably at least until September), and is now accompanied by a hot wind. This is the perfect weather for a sweaty day in the field. It's the beginning of our second week.
 
 We completed the planned gravity profile between Tiryns and Midea (40 points total) and three passive seismic arrays. It was not easy. Another screaming Greek grandmother – the Greek name for them is giagiĆ” (pronounced yaya – with emphasis on the second syllable) – threatened the passive seismic crew (Klaus-G. Hinzen and Gregor Schweppe) until Evi calmed her down and convinced her we were not out to steal her land or the hidden gold. Greek men on mopeds were asking what we – Evi and I, the gravity crew – were doing on their land. Our story was convincing enough: that we are investigating the substructure, searching for local faults. One cute Greek guy asked if we were looking for gold. Apparently everyone believes there are hordes of gold secreted all over Greece. Nearly everyone has a map from someone's grandfather with an 'x marks the spot'. Myself, I would just be happy with a hidden grotto with cool spring water and some shade trees.
Hot but not bothered

Next up, Laser scanning, wildlife, and more! Greek grandmothers.