Archive

Posts Tagged ‘earthquake’

Sentinel-1A Satellite: Transforming the analysis of earthquake data

September 8, 2014 1 comment

We’ve previously written about the launch and progress of the Sentinal-1A satellite, part of the European Union’s Copernicus earth observation project. Although still being commissioned and not yet in full production mode, the satellite recently provided radar imagery from Northern California captured before and after the Napa Valley earthquake on 24 August.

Using a technique known as ‘Synthetic aperture radar interferometry’, two images of the same area were compared to identify areas of significant change. Changes to the ground surface modify the reflected radar signal detected by the satellite, and those modified signals can be plotted as an ‘interferogram’ (Source: Radar vision maps Napa Valley earthquake.) The result is both colourful and striking; the fault responsible for the 6.0 earthquake was confirmed as the West Napa Fault, and both the scale and the extent of the surface rupture was immediately apparent.

Napa Valley Quake interferogram

Napa Valley Quaket: © Copernicus data (2014)/ESA/PPO.labs/Norut/COMET-SEOM Insarap study

Imagery like these examples captured for the Napa Valley quake looks set to transform how scientists and data analysts map and respond to earthquakes. With the launch of second Sentinel satellite (1B) in 2016, the imagery update cycle will be reduced from 12 to 6 days. The timely and open publication of high resolution data to support activities on the ground and post quake analysis after each event, should provide unprecedented monitoring of the Earth’s surface.

 

Advertisements

Always on: The analysts are watching …

August 25, 2014 2 comments

We recently came across the Moves App, the always-on data logger that records walking, cycling and running activities, with the option to monitor over 60 other activities that can be configured manually. By keeping track of both activity and idle time calorie burn, the app provides ‘ an automatic diary of your life’  .. and by implication, assuming location tracking is always enabled as well, an automatic log of your location throughout each day. While this highlights a number of privacy concerns we have written about in the past (including Location Privacy: Cellphones vs. GPS, and Location Data Privacy Guidelines Released), it also opens up the possibilities for some insightful, and real-time or near real-time, analytical investigations into what wearers of a particular device or users of a particular app are doing at any given time.

Gizmodo reported today on the activity chart released by Jawbone, makers of the Jawbone UP wristband tracking device, which showed a spike in activity for UP users at the time a 6.0 magnitude earthquake occurred in the Bay Area of Central California in the early hours of Sunday 24th August 2014. Analysis of the users data revealed some insight into the geographic extent of the impact of the quake, with the number of UP wearers active at the time of the quake decreasing with increasing distance from the epicentre.

How the NAPA earthquake affected Bay Area sleepers

How the NAPA earthquake affected Bay Area sleepers.

Source: The Jawbone Blog 

This example provides another timely illustration of just how much personal location data is being collected and how that data may be used in ways never really anticipated by the end users. However, it also shows the potential for using devices and apps like these to provide real-time monitoring of what’s going on at any given location, information that could be used to help save lives and property. As with all new innovations, there are pros and cons to consider; getting the right balance between respecting the privacy of users and reusing some of the location data will help ensure that data mining initiatives such as this will be seen as positive and beneficial and not invasive and creepy.