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Das Projekt GANSSER

Il Regno del Bhutan si trova nell’Himalaya orientale. L’isolamento volontario è il tratto che contraddistingue geograficamente il paese: solo un numero ridotto di stranieri è autorizzato a visitarlo e questo avviene sotto la guida delle agenzie di viaggio del posto. Tali limitazioni mirano a preservare le tradizioni e a mantenere intatta la cultura locale, ma generano anche un effetto secondario: rispetto alle regioni vicine, nel Bhutan la natura del sottosuolo geologico è poco conosciuta.

Il Bhutan rappresenta infatti una delle rare regioni al mondo rimaste ancora inesplorate. Malgrado la sua posizione all’interno della catena montuosa dell’Himalaya – che, al convergere di due placche continentali cresce ogni anno da due a quattro centimetri – si è praticamente all’oscuro di tutto ciò che concerne il pericolo sismico. Come testimonia un numero cospicuo di forti scosse telluriche che hanno devastato vaste regioni dell’Himalaya, in generale, queste zone sono a forte rischio sismico. Negli ultimi 120 anni, invece, la parte occidentale del Nepal così come il Bhutan ne sono stati risparmiati. Questo porta a chiedersi se il rischio sismico in queste regioni sia effettivamente più basso o se il periodo in questione fosse rimasto eccezionalmente calmo.

Installazione di una rete sismica temporanea nel Bhutan

È per rispondere a queste domande che nel 2013 il Servizio Sismico Svizzero (SED), in collaborazione con il gruppo Sismologia e Geodinamica del Politecnico federale di Zurigo, installerà e monitorerà i rilevamenti di una rete sismica temporanea nel Bhutan. I dati registrati aiuteranno a conoscere meglio sia la natura dei sismi della regione sia le strutture litosferiche della catena montuosa dell’Himalaya. Grazie al sostegno del Fondo Nazionale Svizzero (FNS), nel Bhutan i sismologi del Politecnico federale di Zurigo potranno riallacciare una lunga tradizione di ricerca svizzera. Quasi 30 anni fa infatti, Augusto Gansser, deceduto nel 2012, ha portato a termine la prima cartografia geologica del paese.

Il 7 gennaio 2013, una squadra di sismologi e di tecnici si recherà nel Bhutan per installarvi 38 sismometri. Nel corso dell’anno, altre spedizioni garantiranno la manutenzione delle stazioni e il funzionamento del flusso di dati. Una tesi di dottorato fornirà a due persone il contesto adeguato che permetterà loro di valutare i dati registrati. La relazione amichevole instaurata con il servizio geologico nel Bhutan garantirà inoltre che le conoscenze acquisite vadano direttamente a favore del paese.

Dal 7 gennaio 2013 un gruppo del SED si trova in Bhutan per installare, in collaborazione con il gruppo di Sismologia e Geodinamica dell’ETH, una rete sismica temporanea. Il progetto di ricerca finanziato dal Fondo Nazionale Svizzero per la Ricerca Scientifica (FNS) viene portato avanti con il deciso sostegno e la collaborazione dei nostri colleghi bhutanesi, che possono utilizzare i dati qui acquisiti come dati di base in ulteriori progetti (ad esempio per la realizzazione di una mappa della pericolosità sismica). Qui pubblichiamo quotidianamente i brevi testi sull’attività e sulla vita in Bhutan, inviatici come SMS o email dai nostri colleghi.

Informazioni sul progetto GASSNER, che è di contesto a questa attività, sono disponibili qui di seguito e sulla pagina del progetto.

Friday, February 1, 2013 (György Hetényi)

After we installed the last station at a newly improvised site near Thimphu, and after repairing the last cables to bring current at another station near Thimphu, all field participants are more relieved. Today, on the last day in Bhutan, they packed away the remaining material in the storage room and spent a few hours free time in the capital before transferring to Paro, a town close to the airport. All of them will depart back to their home tomorrow morning, with a well-done and complete station network installation that, we hope, will run smoothly and safely. Our first maintenance visit is planned for April.

Wednesday, January 30, 2013 (Katrin Plenkers, Team West)

Our expedition will end very soon. In the remaining two days we have to install three more stations. Without the help of our Bhutanese colleagues it would be very difficult. They have their contacts and organize for example in no time an electrician to install an electrical socket. Beside work they find it quite amusing that we still can't handle the amount of chili they add to the food. Only yesterday we both had to cry because of a very spicy chili salad.

Monday, January  28, 2013 (Katrin Plenkers, Team West)

After a night in Thimpu we are driving towards South to install stations bhw04, bhw05 and bhw06. Yesterday we installed bhw08 in an outreach center of a hospital. The building is most of the time empty (good for our measurement). It is only used for special events like vaccination programs, health lessons or elections. We had beautiful conditions to install the station including a sunset on snowy mountains.

Sunday, January 27, 2013 (Men-Andrin Meiner, Team East)

After driving on hilly roads for three weeks we found ourself on a flat road again. Now we are in Samdrup Jongkan, a town at the Indian border. Here in the Southeast of the East array we plan to build two more stations. The sites we haven investigated back home are a prison and a crematorium. We prefer to install the stations at schools and will first ask there.

Saturday, January 26, 2013 (Men-Andrin Meier, Team East)

At the moment we are having breakfast in Wamrong. With this new energy we will install two more stations today. John and Gayley have to drive back to station bhe05. The station hole was made too big. Nevertheless we are on time and sure to finalize everything in the time being.

Thursday, January 24, 2013 (Men-Andrin Meier, Team East)

Today we fixed some problems at the station near Trashigang, the one we have installed yesterday on a hill. Again the local community was very supportive. Additionally we installed station bhe06 further South. Tomorrow we will head towards the Indian boarder and from there on we will drive northwards.

Thursday, January 24, 2013 (Katrin Plenkers, Team West)

To day we are very pleased to stay over night in the royal guest house above Damphu. It is located in a remote forest on the top of a hill. We will sleep in the staff guest house with simple rooms apart from beautiful painted wooden walls. We enjoy the quietness and exotic birds flying around. These attitudes make the place to a perfect site for station bhn03. We installed it in an abandoned store house nearby.

Wednesday, January 23, 2013 (Men-Andrin Meier, Team East)

To reach the site of station bhe09 we had to drive through estimated 100 switchbacks. As we finally arrived on the top of a small hill we discovered an idyllic town. The farmer families living there were happy to be involved in a scientific project. They assisted in building the station and offered us tea and some snacks. We owed their generous help with a small contribution to the so called "community budget".

Tuesday, January 22, 2013 (Men-Andrin Meier, Team East)

Half of the group went back to Trashigang to load instruments and material. The other half installed a new station (bhe14) in Trashiyangtse close to the Chinese boarder. They have to stay over night as the way back would take too long.

Tuesday, January 22, 2013  (Eszter Kiraly, Team West)

After waiting for a long time for keys and an electrician we finally installed two stations in school buildings. One of the directors offered us a really good tea with coffee taste. Now we are heading back to Wangdue.

Deployment of the temporary seismic network in Bhutan, half-time summary

After preparation and shipping of our instruments during Autumn 2012, project GANSSER finally started its field operations early this year. From their arrival to Bhutan on January 9th, eight seismologists (six from ETH Zürich, one from France and one from the US) work on the installation of 38 broadband seismic sensors across the country until the end of the month. Below György Hetényi gives a half-time summary of the events:

We spent the first few days on acclimatizing to the new time-zone and buying further equipment in town. One of the challenges was to get sand, of which the river bank had not enough but the minimum quantity to purchase was “one truck”, about 20 times more than we needed. At the end, we negotiated at the construction site of the new Supreme Court to get a couple of bags, which we bargained against a few empty but good quality sand bags! The other challenge was to wait the late delivery of 40 car batteries and 30 large plastic barrels from India patiently – at the end the delay was only slight. By the weekend (12-13th), everything was set to start working in the field.

We split into two groups with two vehicles each. The East Team had to install 18 stations. The West Team (20 stations to install) started installations near Thimphu, and then left to the next valley to install the northernmost stations of the array on the next three days (14-16th). Everything went easily and smoothly, people were open to have stations in their house, office or school storage. Our Bhutanese colleagues were very efficient in negotiating the sites, and our drivers did an excellent job and also helped us to construct the sites. We did not encounter problems bigger than no water in a hotel on one morning, or some rough roads late in the evening. The installation is at very good stage, and we look forward to the coming days to see the development of the network.

Monday, January 21, 2013 (Men-Andrin Meier, Team East)

Instead of the predicted snowy weather we enjoyed a beautiful day continuing our work. The team in charge of the installation of the station in the furthest East of the array (bhe14) were stuck in a muddy road and had to turn. We will try it again tomorrow!

Monday, January 21, 2013 (Katrin Plenkers, Team West)

Yesterday on the way back from our stations "bhw08" and "bhw09" our driver suddenly stopped and bowed in the middle of a mountain road. The only thing we saw was a cyclist in sportive cloths passing by. It turned out that this man was the former king. The king and its achievements are highly regarded in Bhutan.

Sunday, January 20, 2013 (Men-Andrin Meier, Team East)

Arrived today in Trashiyangtse in the Northeast of Bhutan. We already installed four stations in Central Bhutan and today two of the total 14 stations in the East. Country and people are very impressive even though life is pretty simple but important things seem be available. Many things work here that one can't find at other places.  For example free access to education and public health services and they really care about their environment.

Saturday, 19 January, 2013 (Katrin Plenkers, Team West)

Snow in Thimhu. People of all ages engage in snow ball fights. First snow of the year always is a public holiday. Happens not every year. Luckily shops are open and we can buy cables and wood to install another station today.