The Sound of Sliding

December-2013-coverWhen a landslide tore through a remote Alaskan valley in July, no one was there to bear witness. But hours later, geoscientist Colin Stark of the Lamont-Doherty Earth Observatory spotted the event in the pattern of seismic waves passing through the Earth’s crust. Within days, using data from earthquake sensors and satellite images, he and colleague Göran Ekström were able to estimate, from their lab in New York, the landslide’s size, and even determine its path.

The forces generated by landslides aren’t as well understood as those that occur during earthquakes, partly because landslides often strike unpopulated areas with no observers. As a result, landslides leave few clues to how they unfold, making it difficult to predict them or prevent damage the next time.

When humans do live nearby, the consequences can be dire. In 2000, a landslide on the Chinese-Indian border went unnoticed. The rubble created a dam that broke a few months later, killing about 130 people. With better tools for understanding how landslides evolve, where they flow and why some parts of slopes crumble as they do, “these people would not have died,” Stark says.

Ekström and Stark’s collaboration began when Ekström was investigating an apparent series of earthquakes in Taiwan. The seismic data generated by the quakes seemed odd, so he approached Stark, an expert on landslides in the region. To understand the unfolding event better, they created an algorithm combining data from satellite imagery and the international network of seismic stations. The algorithm showed the event was not an earthquake at all, but a series of landslides.

Soon, Ekström and Stark expanded their work to investigate landslides elsewhere. To trace the footsteps of a landslide, they begin by using seismic waves to calculate its force. Then they overlay satellite images to see how far the rubble traveled. Using these parameters, they can calculate a landslide’s mass and acceleration — information otherwise impossible to glean, even for those videotaping the event.

Recently the two used their method to unearth crucial clues about 29 known landslides and discover previously unknown events, including a series of seven landslides in India in 2010. This kind of knowledge, they say, could eventually help researchers — and residents — steer clear of danger in advance of an event.
First published in the December 2013 Discover Magazine [html] [pdf]



Satellites to Monitor UN Forest Protection Goals

VTT.deforestation.homepageClimate change negotiators agreed Sunday to monitor deforestation and to pay developing countries for keeping carbon trapped in forests. To measure just how much forest those countries are conserving, the United Nations Collaborative Program on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD+, to its friends) will rely on a complex system of satellite measurements and field checks. The agreement is a victory for advocates in the research and conservation communities. Yet they face a lot of work implementing the program.

Many countries and agencies already have experience conducting their own long-term monitoring, but the programs often differ in their goals and methods. That makes their data hard to compare. For example Brazil spent US $1.4 billion on a satellite system a decade ago for monitoring the Amazon, but some researchers accused it of being more of a drug-smuggling interdiction tool than a forestry tool. And the U.S. National Oceanic and Atmospheric Administration (NOAA ) has been monitoring wildfire-driven deforestation since the 1980s, but that is not suited to monitoring illegal logging because the two forms of deforestation occur on different timescales. Earlier this year, Nature published a commentary by researchers and satellite builders calling for a single international standard for forest-monitoring data.

A Finnish-led team has been working on a more technical forestry problem: how to combine the various bands of data satellites can collect. Optical data, such as that provided by the Landsat system, are common, but do not penetrate the clouds that often cover tropical forests. The team found that they could boost their ability to estimate forest cover and degradation by including radar data, they reported earlier this year in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. The project, called ReCover, collected satellite data in multiple bands from forests at five study sites and compared satellite-based interpretations to measurements of forest cover and quality on the ground. Their first-pass analyses achieved from 75 to 91 percent accuracy in forest classification, depending on the method, but combining methods should help them improve.

First published on IEEE Spectrum’s Tech Talk blog: [html] [pdf]

Remote Mappers Enable Relief to Reach Filipino Typhoon Victims

The typhoon that hit the Philippines last week killed thousands of people and displaced hundreds of thousands more, according to the BBC. The damage to infrastructure and the dislocation of all those people make it difficult for relief agencies to know where to route aid. Yet this typhoon, called Yolanda in the Philippines and Haiyan elsewhere, hit just as the technology to update maps and sift through social media is maturing. Filipinos and their faraway friends may be in the best position yet to respond to a typhoon, thanks to better digital coordination among volunteers.

Read the rest of this post at IEEE Spectrum’s Tech Talk blog post [html] [pdf]


UCSD researcher shot by cofounder

homecoverOn September 18, former Traversa Therapeutics CEO Hans Petersen went on a shooting spree. One of two people wounded was molecular biologist Steven Dowdy, a professor at University of California San Diego (UCSD) School of Medicine, in La Jolla, and cofounder of Traversa, according to a San Diego police report. Petersen has pled not guilty to charges of attempted murder and awaits trial. Petersen and Dowdy set up Traversa in 2006 to commercialize two promising short-interfering RNA (siRNA) delivery technologies licensed from Dowdy’s UCSD laboratory. In 2010 the board of directors asked Petersen to leave, citing the growing complexity of operations, a decision Petersen blamed on Dowdy, according to the UCSD professor. But Dowdy says he had no vote on the board: “I was not the grand poobah of Traversa.” Petersen’s protracted departure coincided with a period in which the pharma industry shied away from RNAi research (Nat. Biotechnol. 29, 93–94 (2011)). The company’s main delivery technology, a fusion of a protein transduction domain and double-stranded RNA binding domain (PTD-DRBD), capable of chaperoning siRNAs through cell membranes to silence genes, only worked at low concentrations. But at the higher siRNA concentrations necessary for clinical trials, it precipitated, Dowdy says. Traversa developed an improved version by late 2011 and decided to focus on that, returning the license for the second siRNA delivery technology ribonucleic neutrals (RNNs) to UCSD. Even so, Traversa failed to attract Series C funding and in April 2012 filed for bankruptcy. Dowdy’s UCSD laboratory meanwhile made more progress with RNNs. He and ex-Traversa CSO Curt Bradshaw have since launched another San Diego–based startup, Solstice Biologics, to capitalize on that technology. In January 2013 Solstice reported an $18-million Series A funding round. Dowdy is recovering from his gunshot wound and says he is “looking forward to getting back into my laboratory and doing science.”

First published by Nature Biotechnology [html] [pdf]

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