3.1. Natural Hazards
Geomorphology was revealed as one of the most important factors influencing landscape development [4]. As a
unique and poorly known tectonic structure, the Philippine-northeast Indonesian region lies at the intersection of
four major lithospheric plates: the Southeast Asian, Philippine Sea, Caroline (Pacific), and Indian-Australian[13].
The resulting subduction zone has dominated the Neogene tectonics of the Philippine-northeast Indonesian region
which has high rates of volcanism, earthquakes, and mountain building. In our study location, there are three active
volcanoes (Karangetan, Ruang, and Tangkoko) and two inactive but morphologically young volcanic centres
(Duasaudara and Klabat) [14].
It has been confirmed that the volcanic Mount Karangetan (1762 m asl) erupted 19 times between 1675 to 2013
[15]. The active volcano of Ruang (722 m asl) last erupted in 2002. Mount Tangkoko (1149 m asl) is one of four
active volcanoes on the northeast tip of Sulawesi and last erupted in 1880. Figure 2 shows the location and the
eruption history of these active volcanoes since 1960.
This has enormous impacts on the landscape and its people. It is evident, from our observations, participatory
activities, and locally reported knowledge, that the benefits of the volcano outweigh the threats to the people and
volcanic activity greatly improves the productivity of the land. The soil quality on Siau Island is much better than on
other small islands and this has positively affected livelihoods by sustaining a profitable agroforestry industry. In
Kinali village, the majority people derive their livelihoods from the planting and harvesting of good quality nutmeg