Project HERACLES : Fieldwork Part 2: 3D Laser Scanning , Finishing Gravity, and the Lady Beekeeper

Our lean mean FARO scanner

3D Laser Scanning: what is it and what can you do with that? A 3D scanner basically takes 100,000 or more samples per second of an (at best stationary) object using laser range-finding, providing a point cloud that can render a highly accurate reconstruction (especially with the addition of a camera). Our new scanner from FARO is smaller-faster-better (and lighter - it can be taken as a carry-on, for example, on an airplane). These types of (active) scans are most useful for reconstructions and as an aid to modeling - the uses are varied, ranging from architectural planning to crime scene investigations (heavily alluded to in Primary Fault) to archeological site investigations (featured in Shaky Ground). Here, for example, one of our published scans from Roman ruins in the middle of Cologne.

I reported last time about our cleaning efforts prior to scanning - absolutely essential for getting a good scan. Luckily the east wall in Tiryns and the north wall in Midea (no direct links to either of the sites - but these links are very useful for background information) were cleaned for us by the crews at both sites for which we are tremendously grateful (thanks to Frau Dr. Demakopoulou, former archeological director at Midea and Frau Dr. Papadimitriou, Eforia of the Argolis, also participants in the HERACLES project, for their organizational help).

The brawny man on the right made the Tiryns east wall pretty for scanning.

 The scanning crew Klaus-G. Hinzen and Gregor Schweppe (also the passive seismic crew - geoscientists must be flexible, versatile and photogenic - WORD!) have made a plan of attack that includes the use of opaque white balls on broomsticks (geophysicists are also resourceful!) placed between the fallen rocks on the wall(s). The balls allow near-perfect alignment of the side-by-side scans. 

Balls on broomsticks amid a Bronze Age Cyclopean wall

 The new scanner needs all of 10 minutes to do a complete 360 degree color scan and even less for black and white. There is barely enough time between scans for the crew to enjoy the spectacular view from Midea. 
 

A momentary respite from the heat and wind to cool the scanner

Heat and wind - significant wind - conspire to slow down and even stop the measurements, especially when the scanner begins to overheat (at around 60 degrees Celsius). But the car air-conditioner serves as a quick cooler-downer (creativity!), the only casualty being Gregor's temporarily frozen hands.

Meanwile, the gravity crew, Evi Seferou and I, finished with traipsing around the Midea acropolis, concentrate on taking gravity measurements at the bottom of the hill - gaining profiles from different directions. After finishing the northernmost reach of our N-S profile, we start out on an E-W dirt road that looks promising because it seems less frequented by vehicles. 

Before we'd gone a scant kilometer, we encountered the end of the road and the beekeepers, a Greek giagiá (and the last in the series) and her husband clad in thick white linen/cotton suits and wide-brimmed hats with face-protecting nets. Evi and I - standing just a few meters from the first of the bee boxes - are wearing black T-shirts. The bee man points at us (and the bees who are making passes at us) and tells us bees hate black. While we hurriedly take our last measurement, the man asks us if we are the ones who have come to count the bees. Instantly distracted (not that difficult, to be honest), I ask (through my translator Evi, of course), so how do you count bees? Turns out that you don't count the bees, you count the boxes - and there are approximately 10,000 bees in a box.

The Greek bee lady and a few of her bees

We adjourn just after and follow the beekeepers to their house in the village of Midea to purchase some of the honey. Because it is a Greek grandmother we are commanded to drink Fanta (you are much too thin! Drink! Drink!) and taste the honey (fabulous). 

The bee lady proceeds to show us pictures of her children (and grandchildren) and asks me questions in Greek, first in a very slow cadence and then louder and more insistent - the international solution to speaking to someone in a language they don't comprehend. Evi is trying not to pee her pants in laughter, especially as she's yelling back answers to the questions - repeatedly - while I try to smile nicely and look like I know what the hell is going on (all of the rapid conversation is not being translated to me - for which I'm grateful, I think). "Is she married!? Does she have any children!?" "Yes!" "She has a son!" And the Greek grandfather meanwhile is mumbling epithets ranging from the mismanagement by the government of everything to the end of civilization as we know it. After we pay for the honey and leave, I realize this is one of those moments that will live with me forever. And if I can't find a way to fit that into a story some way somehow, then I'm not much of a writer, am I?

The guards at Midea

The guards at Tiryns

A few days later, and it's already time to leave. We bid farewell to the environs, to the heat, to the culture, and to the helpful guards at both Midea and Tiryns

A free Greek spirit out for a stroll on Midea

A Helen of Troy contest? We never found out.

Fredocino: the only antidote to the searing Greek heat

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 34^o 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 giagiá (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.

HERACLES: Archeoseismology in Tiryns, Greece, Year 2

T-3 days and counting to take-off. Okay, geophysical field work is not as exciting as going into space, granted, but for a solid earth geophysicist, the earth's surface - and near surface - is not only The Final Frontier, it's the only frontier. Planetary, oceanic and atmospheric geophysicists - your frontier (and mileage) may vary.

The pile of things we have to load into our departmental VW Caddy is growing by the minute. Literally. Saturday we will hit the road, driving first from Bensberg, Germany to Ancona, Italy (it's where the calf bulges out on Italy's boot). Getting on the car ferry. Then after debarking from Patras, Greece, driving the rest of the way to Tiryns where we hope to arrive on Sunday evening (and immediately descend on Scuola, our favorite Italian restaurant - even if it is in Greece, they have the best Caesar salad I've ever had in Europe).

Last year we had a monster Mercedes van from the Sonderforschungsbereich 'Our Way to Europe' of the Uni Cologne. It even had the motto, 'Our Way to Europe' painted on the side. Given the shaky nature of European relations at the time, we covered it up with our magnetic, Erdbebenstation Bensberg sign, hoping that wouldn't incite the Greek natives to come at us with pitchforks and torches quite as much. This year we're leaner and meaner since we're not taking the seismic refraction equipment with us. The passive seismic stations are still in Greece from last year where they've been recording local events for the past nine months, powered by battery and solar panels.

Our work this year will mainly be concentrated in Midea (we hope - we still haven't gotten the permission to work there - ah, Greek bureaucracy!), another fortified palace ruin on its own hill about 7 km northeast of Tiryns. (updated: we got the permission today - T-2 days. Do they read blogs there?)

The excitement (and the terror) of this year's field work is that we have purchased a differential GPS instrument that we'll be using for the first time in Tiryns/Midea and we'll be 'test driving' our new (also leaner and meaner) 3D laser scanner. Most field geophysicists are uniquely suited to these kind of experiments that I call, 'let's take a bunch of new equipment we've never tested before and go out in the field.' That's not because we're so smart, it's because we're flexible. We have to be. When you have cables and electronic devices and sensitive instruments, combined with weather extremes, precipitation and the unknown variables that always come into play during a measurement, something always goes wrong.

But it pays to be philosophical (translate: stock up on ouzo and Retsina and Mythos).

This is a big reason to look forward to the end of the working day at Tiryns.

 Our measurement plans this year include gravity measurements - this time with an ambitious plan to extend a profile from Tiryns to Midea - passive seismic (H/V), Transient electromagnetics (with a Greek colleague), and the laser scanning.

Dida from Tiryns

Käse from Anthemion House

Barbara from Midea

Our Greek colleagues from the animal world will be waiting for us as well. (Note to self: don't forget the dog and cat treats).






I'll be posting on our progress (with pictures) on the journey to Tiryns (it will be my first time to cross the Italian Alps) and, time permitting, on the measurements.

Notes from the field: Tiryns, 2012

At the beginning of our last day in the field, the sun was already well above the ruins of the Mycenaen castle in Tiryns. We had to wait for the GPS to wake up - he'd been increasingly sluggish the last week. Then we made some random gravity measurements and a few quick profiles before the van had to be packed for the drive back to Germany (on the Superfast ferry from Patras to Ancona, Italy and then overland). Most of us flew back to Cologne from Athens.

Looking back, three days later and home in rainy Cologne, it's amazing all the data we collected: passive seismic, P-wave tomography, S-wave tomography, active seismic (in place until next spring), gravity, and differential GPS locations for almost everything. Hector, our doctoral student also did some structural geology measurements.

It's been a field campaign of varying length. A couple of us had been there for four weeks at that time, others three weeks. I think I could have handled another week, but then would have come to the end of my endurance. Once you're over fifty, you really feel it in your bones when you're measuring in 35^oC for eight hours a day. I wouldn't have been able to stand it if it weren't for my lovely and capable measuring partner, Jana (featured below).

 A girl and her differential GPS. It's not easy looking good in the field, but Jana managed it every day.

Next year we'll go back to uncover Medea's geophysical secrets.

A pictorial journal shows the highlights of our Odyssey along our appropriately-named project HERACLES.

The van with its Uni Cologne logo - driven from Cologne to Tiryns and back again.

A panoramic view of Tiryns castle from the east

West view of the castle from the aptly named Mosquito Alley. A mini seismometer array lurks in the foreground

 

Science in Action! Here's the newly designed shear wave source being applied to a refraction line on Mosquito Alley.

Our hotel pool at Anthemion House and a view to Napflion and the hills beyond. Unfortunately, we could not enjoy the pool as much as we would have liked due to just being too darn tired at the end of the day.

Dida, the dig Hund helping Gregor analyze the day's data.

Heracles : Report from Tiryns, Week 1

HERACLES, our archaeoseismological (big word, eight syllables, wooh) project in the ruins of the Mycanean Palace in Tiryns started last week. I won't be joining the crew for another week, but I do have pictures!

The gravimeter that has my name on it. He's waiting patiently for my arrival.

Not a field of flowers, but a field of seismometers. With their own sun.

Every dig needs its own dog. He has a Greek name (Dida) and a German one (Wurst).

Archeologists and Geoscientists of all sizes and nationalities working together. Yes, it can be done.