Semeru volcano erupted on 4 December 2021 and affected thousands of people living around the volcano. The National Agency for Disaster Management noted that there are 48 people killed, 27 injured, and 10.571 evacuated. As a country that is located in the ring of fire, Indonesia is prone to natural disasters like earthquakes and volcanic activities. However, the Semeru volcano eruption is different from other natural disasters in this country. Experts have revealed that the Semeru volcano eruption is not just a natural disaster that occurred naturally. Aside from the endogenic factor, this eruption is also perpetuated by extreme rainfall that is triggered by climate change.
Eko Budi Lelono, the Head of the Geological Agency of the Ministry of Energy and Mineral Resources, explained that the Semeru volcano eruption is also triggered by external factors. It is because the seismic record is relatively low, and there is no significant change in magma supply activity throughout November and before the eruption. Furthermore, extreme rainfall that occurred around the top of the mountain has collapsed part of the volcano’s lava drome, thus triggering the eruption.
Asides from that, an expert from Padjadjaran University also explained that extreme rainfall has also caused cold lava floods around the Semeru volcano. The accumulated volcanic materials are carried by water and flow through the rivers so that the area in the Semeru valley is swept away by cold lava floods. If there is no heavy rainfall, the volcanic materials would not immediately flow through the river and cause a cold lava flood.
The high rainfall intensity in Indonesia at the end of 2021 is caused by the La Nina. This phenomenon is indicated by an increase in rainfall intensity up to 70% in most parts of Indonesia. Previously, BMKG (Meteorology, Climatology and Geophysics Agency) has warned the society of possible hydrometeorological disasters such as floods, landslides, storms, etc. This phenomenon is becoming more frequent due to climate change.
The Opportunity of Soil Fertility from the Semeru Volcano Eruption
This volcanic eruption has created a catastrophic disaster and threatened the lives of many people. However, nature also has its own way to rebuild and recover itself such as by giving more soil fertility. Sand from Semeru volcano contains nutrients that are important for soil fertility, such as calcium oxide (18%), magnesium oxide (3.6%), potassium oxide (2.16%), and phosphorus pentoxide (2.52%). ).
Most farmers in Indonesia have to fertilize their crops with synthetic fertilizers because Indonesia’s soil generally lacks phosphorus nutrients. Therefore, the phosphorus nutrients contained in volcanic sand can be used as a source of natural nutrients to improve soil fertility. This volcanic material needs to be utilized properly instead of being dumped into rivers. However, it takes several years for this volcanic material to be used for soil fertility. Hence, mitigation policy still has to be more prioritized.
The Semeru volcano eruption has shown us that climate change will aggravate natural disasters. As a country prone to disasters, Indonesia has a higher risk of being impacted by climate change. One of the actions that we can do to prevent and overcome climate change is implementing sustainable consumption and production; thus, economic activity can coexist with environmental conservation.
