96/01727 Utilisation of straw and similar agricultural residues

Abstract

Along the SAAVA, two subaereal volcanic fields host known historically active volcanic centers: 1. Methana, with an historic eruption registered in ∼230 BC, and 2. Santorini, with 10 registered historic eruptions, the last one in 1950. Two other volcanic fields are considered as potentially active volcanoes: 1. Nisyros, with historic hydrothermal explosions, the last one in 1887, and 2. Milos, with probable historic hydrothermal explosions during the 1–2nd century AD.In Methana peninsula, volcanic activity was mainly extrusive and effusive. Dangerous pyroclastic products (block and ash flows and related surges) are restricted nearby to the extrusive volcanic edifices. Volcanic hazard and risk in the area is low.Santorini is the most active volcanic field of the South Aegean volcanic arc, one of the world's most violent caldera volcanoes. It comprises two of the three active volcanic Aegean centres, these of Kameni and Kolumbo.The maximum expected event on Santorini is a catastrophic paroxysmal eruption like the Minoan event. The probability of occurrence of such an event in the near future is very low. The most probable event to occur on Santorini is one of post-Minoan type, like those that built up Nea Kameni and Kolumbo.The data available on the post-Minoan activity do not permit an accurate long-term forecasting of the next volcanic unrest. A short-term forecasting for the onset of such a type of activity is considered possible with an integral and efficiently operating monitoring network.In Milos volcanic field, the reactivating of the volcano with hazardous explosive hydrovolcanic eruptions (the maximum expected event) cannot be excluded. The most probable to occur event at Milos is that of a hydrothermal explosion, thus consisting a considerable natural hazard for the area. Volcanic risk in Milos island is relatively very low.On Nisyros, a very young stratovolcano (subaerial cone <160 ka), the hazard and risk evaluation on the maximum expected event, a phreatomagmatic eruption, cannot be estimated accurately. Such an event pose in grave danger not only Nisyros inhabitants but even the nearby area of Kos and the neighbouring coasts of Turkey. The hazard and risk of a hydrothermal explosion is relatively high, as numerous recent hydrothermal craters are present in the Nisyros caldera floor, area that is being visited by thousands of tourists during the summer time.Yali islet is an Upper Quaternary rhyolitic volcanic edifice. The very young age (probably Neolithic) of the last explosive eruption of Yali, lead us to consider even this centre as a potentially active volcano.Regarding the monitoring state of the active and potentially active volcanic centers, Santorini is the only area in which has been set up an integral monitoring system and a Volcano Observatory. Nisyros volcano is not efficiently monitored up to now. The same is valid for Milos and Methana volcanic fields