Landslides kill thousands of people each year worldwide. They can strike without warning, triggered by earthquakes, erosion, or human construction activity. Since 2002, geoscientist Dave Petley has made it his mission to track landslide-related deaths and to collect knowledge about this natural hazard. Officially, Petley is pro-vice chancellor for research and enterprise at the University of East Anglia in Norwich, U.K. But for nearly a decade, he has written The Landslide Blog, now hosted by the American Geophysical Union, which ranges across landslide science, emergency response, and even topics such as depictions of landslides in art. This interview was conducted by email and has been edited for brevity and clarity.
Q: When and why did you start your Landslide Blog?
A: I started my blog in December 2007 as an experiment. Since 2002 I had been compiling data on landslides that kill people around the world, and it was clear to me that the impacts were far larger than had been realized. The blog was an attempt to raise the awareness of landslides and to connect the global landslide community. This consists of a few hundred or so researchers scattered around the world, plus a very large practitioner community of people who engineer slopes to prevent landslides (for example, building railway embankments or road cuttings) or try to fix them when they have occurred.
I now feature current landslide events, research that is of interest to me, the ways that landslides are depicted in art. I sometimes blog about my own research, in the fundamental principles of landslides -- what happens in a slope to change it from being stable to unstable, and how can we use that knowledge to make living by slopes safer -- and in landscape losses: Where do they occur, and why? I tend to write about what interests me, and to see whether people like it. I get on average about 1000 individual visitors per day now, more when there is a large event, so the readership does justify my time commitment, which is a few hours per week. …
It is used extensively by teachers; the practitioner community uses it to link to research; I really enjoy it; and it keeps me tied into my academic discipline.
Q: What are some notable landslides you’ve written about?
A: There were two key events that led to the success of the blog. The first was the Tangjiashan landslide crisis in the aftermath of the 2008 Wenchuan earthquake. I used the blog to follow the desperate, and ultimately successful, efforts by the Chinese authorities to build a diversion dam over this valley-blocking landslide. The blog was very new at that point, but it attracted a lot of attention.
The second was the Attabad landslide crisis in 2010 in northern Pakistan. The landslide itself caused a small number of deaths, but it blocked the Hunza River completely to form a huge lake some 20 kilometers long and about 200 meters deep. The concern was that in the snowmelt season the dam would overtop and then collapse. There were many people in the path of the potential flood.
I used the blog to raise awareness both in Pakistan and internationally about both the crisis and the suffering of the people affected. I visited the site, working with Focus Humanitarian Assistance, a local NGO [nongovernmental organization], and we set up a monitoring team and a separate website that I ran to provide information about the state of the dam on a daily basis. The picture from the government was so confused that this was the only way we could think of trying to provide clarity. I think we had a big, positive impact.
Q: What was it like on the ground in northern Pakistan?
A: The Attabad event was fascinating. I first picked up that something had happened via a news article within a day or two, and I blogged about it. I had a sense that it was major, but there was little information. [The international disaster-relief organization] Focus Humanitarian Assistance contacted me because of the blog posts; they had people on the ground, and were deeply worried. They asked me if I would fly out to take a look with them, so within a few days I caught a flight to Islamabad, and we then drove up the Karakoram Highway to the site. It takes about 24 hours to drive on poor roads. In sections it is necessary to have armed guards.
It was quickly apparent that the landslide was potentially dangerous but that there was a great deal of lethargy at the official level. So we set up the monitoring team and agreed [on] a methodology. I traveled back to Islamabad, and we arranged a conference with NGOs, the government, etc., based on a short report that I wrote. Our line was always that the dam had the potential to be dangerous, but that a catastrophic collapse was not the most likely outcome.
Q: Tell me about a more recent event.
A: The very best of the blog is, I think, illustrated by the  Seti River landslide in Nepal. This first emerged as a catastrophic flood that came out of nowhere, killing about 70 people. I pretty quickly realized that this was probably some sort of landslide event. The series of posts shows how I was able to use the blog to reach out to a range of people who had disparate pieces of information, allowing us to quickly work out what happened. That would not have been possible without it, so in this case (and many others) the blog genuinely provided a scientific service in improving our understanding.
Q: How does the community use The Landslide Blog?
A: The way that I see it is that I have an unofficial pact with the landslide community. I use the blog to provide information about landslides, conferences, papers, and anything else that is interesting. In return, the community lets me know what is going on, and in particular provides information about landslide events that should be in my data set. We all win, and the data is far better as a result, plus it creates a better community.
I am realistic about it—at the end of the day, it is just a blog—but it provides a service at least at some level.
Q: What do you see in the future for you?
A: I continually come up with ideas. The two that I am seriously considering are: a blog on the science of natural disasters, taking events and looking at the underlying science behind them. I would do this on a weekly basis, taking an ongoing event and digging into an aspect of the science in more detail. … There could be an element of examining the statements made by the media to see whether they stand up.
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