May 9
We woke up in Bardibas at the nicest hotel we’d stayed at since leaving Kathmandu. We immediately drove a few km’s to a series of HFT fault scarps that Bollinger et al. had mapped. Some of these scarps were multi event scarps >20 m, but some were very similar in form to the Lave et al. scarps that we had looked at the previous day, ~4m high with some geomorphic development. This was difficult for us to resolve as we aren’t calibrated for the geomorphic rates in this area- we are used to looking at scarps in the desert, and not in the Himalaya with meters of precipitation per year- essentially, we weren’t sure if significant channels are able to be form in the 81 years since the 1934 earthquake occurred in this region, which Bollinger argues is responsible for the scarps here, but Lave et al. argue that similar scarps ~20km to the north are from an 1100 A.D. earthquake. A lot more work needs to be done in this area to resolve the paleoseismic record.
We continued east to a trench site that Deepak and Kumahara (from Hiroshima) had dug a few years previously. There trench was filled in, but the river (technically a khola – Hindi for intermittent stream) had exposed a cut through sediments which showed the Pliocene-Pleistocene Shiwalak formation in an angular unconformity below Holocene-Pleistocene fluvial gravels. The Shiwalak formation makes up much of the southern Lesser Himalaya, and is essentially a sequence of Himalayan fluvial deposits- similar to what is now found in the plains below the Himalaya, but now lithified, lightly folded, and tilted- in this area they were south dipping.
We drove back to the highway and headed west. The highway here is a two “lane” road that is essentially the i5 of Nepal. However, it is very slow to drive on, occasionally (and without signs) turns to gravel, has goats, cows, pigs, chickens, dogs, monkeys, children, tractors, buffalo carts, bicycles, trucks, busses, motorbikes, and cars traveling on it without many rules. It is slow going, but is faster than driving in the mountains. Everyone is constantly honking and driving around eachother.
We saw a few chimneys from brick ‘factories’- essentially large kilns where they use coal to bake local sediments into bricks. We are starting a project to map the orientation that these chimneys fall- we hypothesize that they may indicate the direction of strong motion, but we need to test this with real data. Most of which we’ll collect in Kathmandu, but the 6 or so chimneys that we found on the plains are worth noting.
This took a few hours, and then we stopped for lunch. The traditional Nepalese lunch is dal with rice and some vegetables. It is very good and heavily spiced.
We continued west, and went to a few new spots to look for possible future trench sites, as well as to check for surface rupture- although at this point we’d already checked the most likely locations. The best elevation data we have in this area is SRTM (Shuttle Radar Topography Mission) data which is 90m resolution. Its like looking through foggy goggles compared to the 10 or 1m lidar data we are used to working with. The first site we went to was a bust. The second site was informative, but also not a good trench site. There were 4 or 5 flights of terraces above a beautiful village (all of the kids here’s smiles are amazing). The first two terraces were back tilted close to the fault scarp- which is what is expected in a thrust fault, but was very cool to see demonstrated.
It was getting dark at this point, so we got back in the car and drove west another few hours, stopping for chai with buffalo milk (standard), and finally got to a hotel in Hamauda, which is a little bit into the mountains again.
May 10
We woke up and started driving again, this time heading west to Bharatpur Dun (Dun means valley in Hindi). This is an unusual basin which is behind the HFT, but before the MBT – the next major thrust fault in from the HFT. We stopped for breakfast- this was the biggest city we’d been in since leaving Kathmandu. There wasn’t much noticeable earthquake damage here- like most of the south.
We continued driving, we planned to make it to Kathmandu that night, and it was a long drive (despite the relatively short distance) across the mountains. We stopped to look at an exposure of the MBT. It was highly sheared material- it actually looked a lot like the ‘blue goo’ of the Franciscan formation in Northern California. The fault had essentially taken whatever rocks where here and pulverized them into a weak clay-ey material.
We continued driving- next stop was a few outcrops of the MCT- the next thrust inbound from the MBT. Here we looked at high grade metamorphic rocks- spotted hornfels, gneiss, garnet schists with beautiful folds. We gave a bunch of chocolate to local kids here and it was fun- they know the word chocolate and would come running to the truck. This site was where Deepak’s university takes their students to do field mapping. They spend 3 weeks doing a strip map across the Himalaya- which is incredibly impressive if you could see the terrain. The roads here have 1000′ near vertical drops down to the rivers, and thousands of feet up to the tops of the mountains. There is tons of vegetation, and it must be quite challenging to map.
Finally we started to get close to Kathmandu. We could tell there was more damage than there had been in the south. As we were driving in, we saw a bunch of ambulances, and Deepak got a phone call. Apparently there was a M 4+ aftershock, which with the state of many of the buildings (not collapsed, but damaged) could easily injure or kill people.
We stopped at Deepak’s university. His geology department’s building had been condemned. Interestingly, it was built in 1918- and it survived the 1934 earthquake (although a clock tower fell, which was rebuilt, and didn’t fall this time). We saw many of the other government buildings which had been heavily damaged also- although all were still standing.
We finally made it back to our hotel in Kathmandu, and after discussing our plans, took a few hours off to explore the area around our hotel, the Thamal district. It was interesting talking to people here- they all spoke English, which was very different from the rural villages we’d been in the past few days.
I met a girl who asked me about the earthquake. She worked at a non-profit women’s center, and was very concerned about problems in Nepal. She talked about how she had plans to go help out in some of the rural northern villages, which apparently had been hit the hardest by the earthquake. People there are wondering how to rebuild- as they need shelter quickly, before the monsoon season hits in the next few weeks. There are shelters and aid coming in, but not enough. I wasn’t sure what to tell her, I’m not an engineer, but the unreinforced or lightly reinforced masonry in the cities performs very poorly in earthquakes, and there are not many materials, or even if there were, there’s not enough money to build better homes with. In villages, there are likely ways that houses could be built better (check out NSET – they have publications about this) but people lack the knowledge to do so. From others, I learned that there are about 2,200 affected villages, and nowhere near enough engineers or materials to help people rebuild in the time they need to. Furthermore, there are significant landslide problems that were initiated by the earthquake, but will be greatly exacerbated by the coming rains. It really does sound like a desperate situation in these areas.
May 11
Our plan for May 11 was to map a large set of ground cracks that follow a trend in Kathmandu. We met with Dipendra Gautam- a student of Deepak’s. He is a civil engineer, and would be our guide for the next few days.
We headed to the area with the cracks, which was southeast of the airport in Kathmandu. We began mapping and talking to locals. They all wanted Dipendra’s opinion of their houses- many of which would be immediately red tagged and torn down were they in the US, but here, nobody has anywhere to go or money to do anything about it. Everybody was interested in what we were doing and were very happy to show us what they saw and describe their experience. Again, there were tons of smiling kids- apparently a theme in Nepal.
We spent most of the day doing this, moving from street to street, making a map and taking pictures of the cracks (some were >1.5 m in height).
The people I talked to today seemed to be most conce
rned about the damage to the World Heritage Sites in Kathmandu, which attract many tourists and are a significant economic driver. Everywhere we went, people were trying to rebuild.
Some houses were rotated or tilted, but very few were destroyed. My estimate is that less than 1 in 2000 (0.5%) of houses were totally destroyed. Some of the tilted homes were probably put on end about 15 degrees, which makes them uninhabitable but probably didn’t kill anyone. Fortunately there aren’t any gas lines here- no fires. We also didn’t find any evidence of liquefaction- which plagued Christchurch after their 2010 earthquake sequence. The GPS data and these observations suggest that the earthquake was very gentle- it moved the surface a lot but relatively slowly. For example, we spent a day investigating the 2014 Napa earthquake this past Fall, and everywhere we went there were tons of broken wine bottles, but here, even in a building that was partially ripped apart by cracks, there were intact bottles sitting on shelves. It really is amazing. People need to tear down their homes and rebuild, but it seems unlikely that this will happen at the scale it needs to. Hopefully another large earthquake won’t happen for a while, but nobody really knows.
Despite all of the hardship, people were still very generous- we were invited to have tea with a family who’s building had been heavily damaged.
At the end of the day, Dipendra took us on a bus- which was quite the experience- and then we walked through one of the world heritage sites that had been destroyed on the way to our hotel. We also saw a large tent camp where some people were relocated to. The city really seems to be getting back to normal, despite the damage and uncertainty. This isn’t to say they don’t have problems and they don’t need help- they do, but it seems that people are trying to get on with their lives.
Tomorrow we will spend mapping chimney damage throughout the basin. In two days time we plan to head towards the epicenter – Gorkha – and will then probably see the really badly damaged areas.
Center for Neotectonic Studies 
Yo Steve(s)! re: the M7.3 aftershock, Did You Feel It? We hope you are safe!
http://earthquake.usgs.gov/earthquakes/eventpage/us20002ejl#impact_dyfi
-Scott
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