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Email: ollie.ballinger@st-annes.ox.ac.uk 

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Building a 3D Model of the Beirut Explosion

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Blast damage assessment in Beirut is being carried out using two-dimensional satellite imagery. These approaches underestimate damage by failing to capture damage done to the sides of buildings. I outline an alternative approach using Open Street Map data to create a 3D model of Beirut and the explosion to analyze directional blast damage.  Satellite Imagery and its Limits Following the recent explosion in Beirut, I built a tool that uses Sentinel-2 imagery to map the destruction caused by the blast. After some trial and error, I arrived at a fairly simple two step process: first, measuring the change in spectral signatures between pre- and post-explosion images. Second, applying an X-Means clustering algorirthm to the resulting image (yielding the map on the right), or taking the absolute difference (yielding the map on the left): Red areas on the left indicate high levels change between the pre- and post- explosion images. On the right, the magnitude, direction, and spectral
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Did Saudi Arabia Know an Attack was Coming?

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On September 14th 2019, a combination of drone and missile attacks targeted Saudi Arabia’s oil infrastructure at the Abqaiq and Khurais Aramco facilities, cutting the country’s oil production by over 50% and leading to the largest spike in the price of oil ever recorded . The attack was particularly embarrassing for Riyadh because billions of dollars' worth of air-defense systems were thwarted by drones that may have cost as little as $15,000 . A year later, the expert consensus seems to be that the attack was successful because the Saudis were caught off guard, with the element of surprise giving the assailants a decisive edge.  An open source analysis of radar interference from Saudi Arabian air defenses suggests that the Kingdom might actually have been expecting an Iranian attack on its oil infrastructure: five days before the attack, a missile defense system pointed at Iran was switched on for the first time at one of the largest refineries in the country. This analysis also
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Calculating High-Resolution Standardized Precipitation-Evapotranspiration Index

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