In this monthly feature, we span the globe to examine Our Changing Landscape with a time series of medium resolution RapidEye satellite imagery. The RapidEye archive dates back to late 2008 and already contains more than 14 billion square kilometers of data. Last month we returned to one of our favorite topics, i.e. volcanos, with a look at the site of a 2015 eruption, and for the September Our Changing Landscape we stay in South America, sticking with the theme, this time stopping at Sabancaya, Peru, the site of ongoing eruptions since 2016.
The RapidEye Constellation
RapidEye is a constellation of five 5-meter (m) medium resolution satellites each offering five spectral bands of information. The RapidEye constellation offers daily revisits to every location on the planet with a huge footprint that is 77-km wide. The data is priced competitively with a starting cost of $1.28 per square kilometer for all five spectral bands – academics do receive discounts. RapidEye adds a fifth band, the red edge, to the ‘traditional’ multispectral set of blue, green, red and near-infrared (NIR). The additional spectral data in the red edge band allows users to extract more useful land ‘information’ than can be from traditional 4-band imagery sources. When RapidEye imagery is ordered as a Level 3A Orthorectified product, images from multiple dates are extremely well registered, making it the ideal data source for Our Changing Landscape.
The Ongoing Eruptions of Sabancaya
Volcano Sabancaya is the center and youngest of a three-crater complex in southern Peru – with Nevado Hualca Hualca to its north and Nevado Ambato to its south. Standing 5,960 meters (19,544 feet) tall, Sabancaya is some 700 kilometers (435 miles) southwest of Lima, Peru and 120 kilometers (75 miles) from the Atlantic Ocean, nestled squarely in the Central Volcanic Zone of the Andes Mountains. The Central Volcanic Zone stretches from Chile to Peru and is dotted with 44 major and 18 minor active volcanos.
Sabancaya has a long history of eruptive activity that dates back to at least 6600 BCE – and in recent history it has seen active periods since 1986 with ongoing eruptions since November 6, 2016. A summary of eruptive history from June to December 2016 shows no less than 13 daily explosions (on average) during the period with some weeks peaking at 30 daily explosions. These eruptions rose to a maximum height of 1,300 to 4,500 meters (4,265 to 14,765 feet) emitting up to 14,859 tons of sulfur dioxide (SO2) per day. While this list is certainly not comprehensive, it does show that Sabancaya killed 20 in a 1991 eruption but no deaths have been listed since – which also lines up with our internet news search. This paper reports cattle deaths in the 1990s around Sabancaya but if you check out Google Earth you will see little human development in the area, so it makes sense that this volcano has not caused massive destruction of infrastructure, etc. Without further ado, it’s time to check out the 5-meter RapidEye archive of Sabancaya to see how the local surroundings have changed due to the recent eruptive activity.
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