**1. Introduction**

Sleman Regency is on the southern slopes of Merapi Volcano, at an altitude between 100 and 2,500 meters above sea level. This regency consisting of 17 districts, 86 sub-districts and 1,212 hamlets. The boundaries of Sleman Regency, to the north, are bordered by Boyolali Regency, Central Java Province. In the east, it is bordered by Klaten Regency, Central Java Province. In the south, it is bordered by Bantul Regency and Yogyakarta City, Yogyakarta Special Region. In the west, it is bordered by Kulon Progo Regency, Yogyakarta Special Region and Magelang Regency, Central Java Province.

Merapi Volcano has been the most active volcano during Holocene time. As strato volcano, Merapi exhibit altwrnating volcanic activities of effusive and axplosive character and self destruction. The explosivity index has involved during the last ten tousand years. The effusive activities were characterized by the occurence

of lava flow, the development of lava dome, and the production of the nuee ardente d'avalanche, called Merapi type (69–74, [1]).

Merapi Volcano since 1768 has recorded more than 80 eruptions. Among them are large eruptions with a Volcano Eruption Index (VEI) of more than 3. Major eruptions occurred in 1768, 1822, 1849, 1872 and 1930–1931. The eruption of Merapi Volcano in 1872–1931 led to the west-northwest. From the big eruption in 1930 until the eruption in 2001 the direction of the eruption changed to the southwest. The 1994 eruption occurred a deviation to the southwest - south, namely upstream of the Boyong River, between the Turgo and Plawangan hills (69–138, [2]).

Of 1.1 million people living on the flanks of the active Merapi volcano, 440,000 are at relatively high risk in areas prone to pyroclastic flows, surges, and lahars. For the last two centuries, the activity of Merapi has alternated regularly between long periods of viscous lava dome extrusion, and brief explosive episodes at 8–15 year intervals, which generated dome-collapse pyroclastic flows and destroyed part of the pre-existing domes. Violent explosive episodes on an average recurrence of 26–54 years have generated pyroclastic flows, surges, tephra-falls, and subsequent lahars. The 61 reported eruptions since the mid-1500s killed about 7000 people (479–502, [3]).

The distribution and run-out distances of these flows have frequently exceeded those of the classic Merapi-type nuées ardentes of the recent activity. Widespread pumiceous fallout deposits testify the occurrence of moderate to large (subplinian) eruptions (VEI 3–4) during the mid to late Holocene. VEI 4 eruptions, as identified in the stratigraphic record, are an order of magnitude larger than any recorded historical eruption of Merapi, except for the 1872 AD and, the October–November 2010 events (1213–1233, [4]). The last eruption in 2010 was one of the most explosive eruptions with a hot cloud range of up to 15 km.

The geologic record suggests the latter, which would place several hundred thousand people at risk. We know of no reliable method to forecast when an explosive eruption will interrupt the present interval of low-level activity. This conclusion has important implications for hazard evaluation (9–50, [5]).

Volcanic eruption contingency plans that address Covid 19 adaptation and involve the participation of children, so as to express their opinions and needs in implementing disaster emergency management.

## **2. Merapi Volcano Eruption Scenario**

The eruption of Merapi Volcano is characterized by the release of surface magma to form a lava dome in the middle of an active crater around the peak. The emergence of new lava is usually accompanied by the destruction of old lava, which blocks the flow, causing lava to fall. The new lava that reaches the surface forms a dome that can grow bigger. The growth of the lava dome is proportional to the magma flow rate which varies up to hundreds of thousands of cubic meters per day. The lava dome that grows in the crater and enlarges causes instability. The lava dome which is unstable in position and pushed by gas pressure from inside causes part of it to collapse, thus forming pyroclastic flows that slide into rivers that originate at Merapi Volcano. The movement speed reaches 60–100 km/hour and will stop when the energy of the motion runs out. Pyroclastic flows are a primary hazard, directly affecting the population, and the most destructive of all types of hazards.

The scenario for the future eruption of Merapi Volcano begins with the formation of a lava dome in the center of the crater on the southeast side. The maximum volume is 10 million cubic meters, and half, as much as 5 million cubic meters, collects into pyroclastic flows. This scenario refers to a large chronology of eruptions in 1992, 1994, 1995, 1996, and 2001. Another scenario is the formation of a lava dome

#### *Participatory Contingency Plan to Covid 19 Adaptation of Merapi Volcano Eruption - Indonesia DOI: http://dx.doi.org/10.5772/intechopen.98360*

with the same volume in the center of the crater on the west – northwest side. The growth of the dome is large enough to cause instability/collapse of the crater wall in the western sector and the southern sector close to the crater opening. This scenario is consistent with the eruptive behavior of 1998 and 2006.

After the phreatic eruption on May 21, 2018, the Geological Agency increased the activity status of Merapi Volcano from Level 1 to Level 2, with a recommendation that there should be no population activity within a radius of 3 km from the summit. Furthermore, in 2019 there were 4 eruptions. On September 22, 2019, the eruption column formed ±800 meters. October 14, 2019, formed a ± 3,000 meter eruption column. November 9, 2019, a hot cloud glided into the Gendol River as far as 2 km, with an eruption column of ±1,500 meters. November 17, 2019 formed a 1,000 meter eruption column. After the eruption on June 21, 2020, there was a shortening of the baseline distance of the Electronic Distance Measurement (EDM) in the northwestern sector of Babadan, with an average rate of up to 11 mm/day. The seismicity increased so that on November 4 2020 average shallow volcanotectonic event earthquake (VB) was 29 times/day, multyphase earthquake (MP) 272 times/day, avalanche (RF) 57 times/day, gusts (DG) 64 times/day, total earthquake energy (Vt and MP) in a year amounting to 58 GJ. Based on these data, the Geological Agency has increased the status of Merapi Volcano activity from Level 2 to Level 3.

The Sleman Government responded and followed up on the change in status by establishing the Merapi Volcano Disaster Emergency Response Status. This determination is the basis for preparing a Disaster Emergency Management Operational Plan. Seven villages in Disaster Prone Area (DPA) III, were designated as potential affected areas, namely the areas of Glagaharjo, Kepuharjo, Umbulharjo, Hargobingan, Purwobinangan, Girikerto, and Wonokerto villages.

In this scenario, people evacuate to reduce risks. Communities are shifting from their higher-risk dwellings to lower-risk shelters. The relationship between the level of risk which is influenced by the position in the disaster-prone area with the status of the volcano is shown in **Figure 1**.


**Figure 1.** *Level of risk, relation of disaster prone area (X) and volcano status (Y).*
