Tracking Vvolcanic Ppumices usingthrough Ssatellites and social mediaSNS

Country/area: Japan

Organisation: Nikkei

Organisation size: Big

Publication date: 12/11/2021

Credit: Kenji Asada,Shoji Yano,Masashi Ijichi,Ryo Namiki,Kazumi Saito,Karina Noka,Tetsuya Kitayama,Harue Matsushima,Akira Shimizu,Yuri Morita,Gaku Ito,Akihiro Tojo


This project was created by Nikkei’s Data Visualization Center, where data journalists, programmers, designers, and photographers work together. Each person brings their unique expertise to each project. 

Project description:

Millions of stones suddenly filled fishing ports and pristine beaches in southern parts of Japan. This extraordinary natural disaster was caused by volcanic pumice originating in the Japan’s Ogasawara Islands, and some feared that they could disrupt important supply chains. Nikkei was the first newsroom to visualize the threat of pumice through an interactive map and an extensive timeline. Our data journalists, together with science writers and photographers, used satellite imagery, analytics from research institutes and social media posts to create this content. Up-to-date information and the projected trajectories of the pumice were quickly used by local governments and fisheries.

Impact reached:

Volcanic pumice has garnered public attention since the eruption of submarine volcano in August 2021. Many photos of pumice were posted on social media, and companies tried to measure the potential impact pumice could have on their businesses. However, there was no place for them to find up-to-date information on the locations of the drifting stones. Our project made this possible. Nikkei visualized locations of pumice on a single map, along with a timeline of important events and social media posts of important moments. Our project became one of the most read pieces of visual content of Nikkei.  

Techniques/technologies used:

Nikkei visualized the locations of pumice through Python and GIS, using data on recent drifts and trajectory projections made by research institutes. Our data journalist also used Sentinel imageries from the European Space Agency to locate pumice flows. Our team incorporated these data into Mapbox to make an interactive experience. For example, our readers can choose a date on the interactive map to see where pumice is expected to drift on that day. They can check the latest information, as well as the past and future trajectories of pumice flows all in our single project.

What was the hardest part of this project?

The trajectories of pumice are influenced by unpredictable factors, such as wind and currents. Only limited amounts of pumice approached Tokyo and other important areas, and our readers’ interest has gradually shifted to measures to address pumice drifts, not just tracking their trajectories. Nikkei interviewed government officials about measures taken and quickly added them to the timeline while upgrading the visual content.

What can others learn from this project?

Our project made it possible for readers to recognize the situation of volcanic pumice at a glance through the interactive map and the timeline-style articles. Moreover, these contents were published within two weeks of the initial reports of massive pumice drifts, meaning the project quickly met readers’ demands. This project also serves as a historical archive of this special natural event by recording extensive information about pumice.

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