Assessing Geotourism Aspects of Ungaran Geothermal Areas for Promoting Sustainable Energy through Volcano-Geothermal Tourist Destination

The indigenous nature of the Ungaran volcano-geothermal area allows us to bring the benefit to its nearest community. Geotourism can be an opportunity to introduce geological knowledge and foster the socio-cultural acceptance of society towards geothermal. This study aims to assess the potential of the study area as tourist destination. The research method is collecting data on geothermal manifestations and volcanic feature sites, quantitative assessment of geosites and geomorphosites, and preliminary hazard risk analysis. Study results identify six geosites: Gedong Songo area, Nglimut hot spring, Diwak-Derekan-Kaliulo warm spring, and Mawar camping area which features a volcanic landscape. Five of six geosites have high geotourism value of more than 0.5 in average, except for Kaliulo site. The recommendation of activities to do are leisure activities in nature, hiking, camping, thermal bathing, horseback riding, and geological excursion.Ttourists should be cautious of potential hazards risk from volcanic gases, hot and acid waters, slippery and unstable areas, landslides, rugged terrain, and extreme weather. A geotourism model is constructed to highlight each site and their attributes to Ungaran volcano-geothermal setting, tourism activities, and possible risks. By exploring the natural and geological richness offered by this destination, tourists will discover the uniqueness of volcano-geothermal tourism experience.


Introduction
Geotourism is a new concept in nature-based tourism that has grown rapidly, simultaneously with educational and sustainable tourism.It focuses on geological and geomorphological elements of the geosites to attract visitors [1,2].Natural conditions in volcano-geothermal areas open up opportunities for various recreational activities [3].The challenging climate and rugged mountainous terrain are suitable for adventure tourism.The existence of hot and warm springs is an attraction as a location for natural hot springs which are beneficial for relaxation and health.Over time, this interest has become increasingly evident with the development of tourism in volcanic and geothermal areas.Even so, people associate it more with nature tourism, not geotourism or ecotourism, especially education-based ones [4].Education-based geotourism aims to foster an understanding of geological phenomena, their benefits and implications for our life.This geotourism sub-sector is part of education which creates holistic access to geoscience knowledge [5].The development of tourism in geothermalvolcano areas can also be used as a means to build broad public acceptance of geothermal energy as a sustainable energy source [6].Although health and safety aspects are important factors in determining tourist destinations, visitors to geothermal-volcano areas are aware that they are 1245 (2023) 012018 IOP Publishing doi:10.1088/1755-1315/1245/1/012018 2 approaching a dangerous area.It should be realized that volcanic and geothermal activities have risks of hazards such as eruptions, volcanic gases, steam and hot water, ground motions, and so on.In order for the development of a site to become a tourist destination to remain safe, the potential for hazards must be identified and mitigated, especially those related to volcanicgeothermal conditions in the study area [3,7].Ungaran is an andesitic volcano, part of the Quaternary Java volcanic arc which is formed from the subduction between the Indo Australian Plate to Eurasian Plate.Lithology of Ungaran volcano and its surroundings (Figure 1) consists of Neogene sedimentary rocks (Tmk), andesite intrusion (Tma), volcaniclastic rocks (Qpkg), Old Ungaran volcanic rocks (Qpj, Qpk), and Younger Ungaran volcanic rocks (Qhg, Qls) [8,9].The remnant of volcanic activity of Ungaran is manifested as fumaroles, altered rocks, steaming ground, and hot springs [10,11].The unique volcanic features, beautiful volcanic landforms, and geothermal manifestations are a good opportunity to be developed as a geotourism site.This research aims to assess geosite and geomorphosite of the study area, evaluate and identify potential hazards.The proximity to various Geological Engineering campuses in Central Java and Yogyakarta makes the Gedong Songo area, Ungaran a good choice of location for studies related to volcanoesgeothermal.The purpose of this study is expected to provide further insight to attract students and geoscientists in developing geotourism models that can be applied in volcano-geothermal areas.

Methods
Geosite mapping and field survey were conducted to assess geological and geomorphological conditions related to the volcano and geothermal activity at the Ungaran volcano area.Geosite selection was based on public information and previous study so that it represents volcanogeothermal diversity, mostly geothermal manifestations as well as geomorphosites with specific landscapes.A field survey is essential to obtain descriptive data and documentation of each site.The geological and geomorphological aspects of each site are based on previous study, map analysis and direct field observation.Documentation consists of coordinate location and taking photos to capture geomorphological conditions, rock/ outcrop condition, and thermal features.Other than geological and geomorphological conditions, information related to the potential hazards was collected.Geosite and geomorphosite assessment used in this research is a quantitative method using five values that define geoconservation and geotourism purposes [12,13].The five values are (1) scientific and intrinsic value, (2) educational value, (3) economic value, (4) conservation value, and (5) added value.Furthermore, each value is divided into 3-5 criteria and then for every criterion, a 0 -1 numerical value is added (Table 1).Existing educational product 0no products 0.5leaflets, maps, web pages 1info panel, information at the site D Actual use for educational purposes 0no educative use of the site 0.5sites as a part of specialized excursions 1guided tours for public Economic value A Accessibility 0more than 1000 m from the parking place 0.5less than 1000 m from the parking place 1more than 1000 m from the stop of public transport B Presence of tourist infrastructure 0more than 10 km ftom the site existing tourist facilities 0. A geotourism map is prepared to show the location of each site with its uniqueness as geosite and geomorphosites.To provide a more comprehensive model of volcano-geothermal based geotourism, a cross section model is constructed with the incorporation of simple geothermal conceptual model, visitor activities, and possible hazard risks along the volcano area.

Geosites Distribution
Based on the field survey as illustrated in Figure 2, six geosites and geomorphosites are selected in the Ungaran volcano-geothermal area.Most of them are geothermal manifestations on a volcanic landscape: hot springs, warm springs, steaming ground, fumarole, and altered rocks.One of the sites is a geomorphosite which represents the volcanic landscape of Ungaran and its surrounding volcano as a part of Java volcanic arc.

. Gedong Songo Temple Geothermal Area
Gedongsongo Temple is located in Candi Village, Bandungan District, Semarang Regency at the southern flank of Ungaran volcano.This is a cultural site of a historical temple that coexist with several geothermal manifestations such as fumaroles, hot springs, mud pools, steaming ground, and altered rocks (Figure 3).Gedongsongo Temple is located at 1,200 msl elevation.It can be accessed easily thanks to the fairly good road infrastructure with an estimated journey of approximately 1.5-hour drive from the nearest city, Semarang.This location is well facilitated and managed by the local culture and forestry service.The morphology of the Gedongsongo area is controlled by the rocks and geological structures present at the site.The lithology of Gedongsongo area is dominated by volcanic breccia and andesitic lava.The northeast-southwest trending scarp can be interpreted as a fault and fracture zone that resulted in geothermal activity on the surface.Gedongsongo area is an active fumarole field, emitting volcanic steam and gases such as SO 2 and CO 2 through fissures.Sulphate hot springs, mud pools, and acid alteration rocks are an indication of upflow geothermal area [11].Apart from the geothermal manifestations, this site was a religious monument from the Ancient Mataram Kingdom which is built in the 8th Century.This temple at its time was used as a place to worship their gods, as indicated by the presence of the statues of Shiva, Mahakala, Nandiswara, and Ganesha.Its location in the highlands is also related to the belief of the Hindu community who believe that the mountain is the abode of the gods and worship at a high place will be closer to heaven [14].

Nglimut Hot Spring
The Nglimut Hot Spring is located in Nglimut Hamlet, Gonoharjo Village, Limbangan District, Kendal Regency.The geosite that was found was the location of a pool with hot springs that had been managed and also used as a tourist spot.It is situated at an elevation of 700 msl and has a relaxing view of forest in a hilly topography.Access to this location is also quite easy, it can be reached by motorcycle and car, with slightly damaged and rocky road access.From the center of Semarang City, the trip will take around 1.5 hours' drive.The uniqueness of this geosite is the discovery of several hot springs that have been used as warm bathing pools.The water temperature in this hot spring ranges from 30°C -45°C.Based on [15], the chemical content of water is a mixture of chloride and bicarbonate water originating from reservoir fluids that underwent a mixing process with meteoric water.

Diwak Hot Spring
Diwak hot spring is located in the residential area of Diwak Village, Bergas District, Semarang Regency.With an hour distance trip from Semarang City, its location is accessible using a car or motorcycle through a relatively decent road access.This thermal manifestation has been used as a hot bathing pool with the only facilities are parking lot, toilet, and bathroom.Diwak hot springs have two separate pools, for men and women.Diwak area is situated on weathered andesitic lava and breccia associated with the Gajahmungkur Volcanics Formation.The chloride water spring indicates the presence of a high permeability zone, which is formed by faults and fractures on volcanic rock formation [16].

Derekan Hot Spring
Derekan hot spring is located near Diwak along the same river valley.It only takes about 15 minutes to get here from the Diwak hot spring.Historically, Derekan hot spring area is an ancient bathhouse located near a Hindu temple called Ngempon Temple (Figure 4).The temple was built around 8 th -9 th century with an architecture similar to Gedongsongo Temple [17].The lithology of the study area is composed of andesitic breccia and tuffaceous sandstone from the Ungaran volcano.It is indicated that the hot spring came naturally due to structural control [18].The geothermal water of this site is characterized by bicarbonate type and the occurrence of travertine layers.This is a result of the interaction between condensate water and shallow groundwater which accumulate CO 2 while water flows laterally to the outflow zone [16].

. Kaliulo Hot Spring
Kaliulo hot spring is located in the Kaliulo Village, Pringapus District, Semarang Regency.It can be accessed from Semarang-Yogyakarta main road and then through the local road which are in rather poor condition.Several hot spring spots appear on the ground near local rice fields, some of them have been accommodated in a pond.This hot spring is quite unique due to its salty taste, where the locals use its water as a thickening agent for making gendar, some kind of rice cake.Travertine deposit is also found as one of the manifestations.The lithology of the surrounding area is dominated by tuffaceous sandstone and claystone units of the Kaligetas Formation.A deep subsurface structural geology inferred by gravity study controlled the hot spring emergence [19].Water geochemistry shows a bicarbonate water type with an anomalously high concentration of sodium chloride and boron from connate water in the Neogene marine sedimentary rock [19].

Mawar Camping Ground
Mawar Camping Ground is a location in the Umbul Sidomukti Tourism area, Bandungan District, Semarang Regency, which has been developed into a tourist location with various facilities.Mawar Camping Ground can be reached in about 1 hour if departing from the center of Semarang City.The price of the entry ticket is Rp.5,000, -for each person, but not including parking fees and specific attraction fees.The location of Mawar Camping ground is at an altitude of 1,265 msl.This site is also considered fascinating because it faces directly towards the beautiful scenery at the volcanic complex nearby where we can view Merbabu volcano, Merapi volcano, Telomoyo volcano, and Pening Lake at the southern view.In the Mawar Camping Ground area, visitors will not only find locations for camping, but there are several facilities for other activities, such as cafes, restaurants, villas, playgrounds, and also horse-riding areas.In this area there is also an artificial cave, namely the Tirta Mulya Cave which was made in 2009.
At the end of the cave, there is a small place which is limited by a fence as a place to enjoy the view of Ungaran volcano up close.

Geosite and Geomorphosite Assessment
Each geosite that has been selected is then analyzed by quantitative analysis with an assessment based on five parameters [13].After the assessment was carried out (Table 2), the 5 out of 6 geosites have an average value above 0.5 and later can be prioritized to become a geotourism area around Mount Ungaran.One of the geosites does not contain most of tourism elements, hence the low assessment value.

Leisure Hiking
This activity can be done at the Gedongsongo Temple area with a specific route facilitated by the site manager.Starting from the entrance, with an uphill path and through several traditional pavilions, equestrian areas, stage areas, lower temple areas (complex I-II), and hot spring pools.Then proceed with hiking through higher temple areas (complex III -V) past several vendor stalls selling food and drinks.Hiking activities carried out in the Gedongsongo Temple area take approximately 2 hours starting from the entrance to the exit.Other than this site, the Nglimut area is also suitable for hiking and sightseeing.The natural ambience of pine forest and waterfall with a serene environment is a relaxing experience for many people.

Cultural Tourism
There are two temple complexes in the research location, namely Gedongsongo temple and Ngempon temple.Both are historical relics from the Hindu culture of the Sanjaya dynasty in the 8th-9th centuries.The management of the temple is under the cultural heritage preservation center.The gedongsongo area offers beautiful views of the slopes of Ungaran Volcano, breezy air and geothermal manifestations.Meanwhile, the Ngempon temple is a former ancient bathhouse which is still being used today as Derekan hot pool.

Thermal Bathing
Several hot springs can be found in the study area: Gedongsongo area, Diwak hot spring, Derekan hot spring, and Nglimut hot spring.All of them are equipped with hot pool facilities from the natural hot spring water.Many cultures all over the world have traditions around hot springs and their utilization [20].Thermal bathing has therapeutic effects that helps us to relieve pain, relax our muscles, rejuvenate and detoxify the body.Its therapeutical benefits are due to the mineral composition of geothermal water.Natural hot springs usually has common soluble elements such as sodium, calcium, magnesium, iron, sulphur, and other trace elements [21].Sulphur-rich water can help with skin problems due to its antiseptic properties.Its healing benefit include treating skin conditions such as dermatitis, psoriasis, and fungal diseases.

Horseback Riding
Gedongsongo temple and Mawar camping ground offer horseback riding experiences for adults and kids.It can be an alternative for those who want to explore the area and are too exhausted to hike.The horse stable can be found near the entrance of Gedongsongo temple.Each horse will be accompanied by an equestrian.Horseback riding usually cost about Rp. 50,000 -Rp.100,000 depends on the package and distance.

Camping
Camping can be an adventurous or family friendly activity.In several sites of the study area, location such as Nglimut Hot Springs area and Mawar Camping Ground also provides an allocated spot for tourists who want to camp.The manager also facilitates bathroom and toilet, water supply, and camping equipment rental to make it convenient for visitors.

Volcano-Geothermal Excursion
The research area is a volcano-geothermal complex from Ungaran volcano activity.Based on the assessment, it meets the parameter of educational aspects of general geoscience, volcanology, and geothermal studies.For the volcanology fieldtrip, it can be suggested to visit and observe the location of volcanic rocks outcrop in the Gedongsongo area.Mawar Camping area is a geomorphosite to witness the development of the geomorphological evolution of Ungaran volcano and its surrounding volcanoes.Geothermal excursions are carried out by observing the naturally occurring manifestations and estimating the potential of geothermal energy resources in this area.In the field of geophysics, the relationship between volcanic features, geothermal manifestation, lithology, and structural geology can be studied in the Ungaran volcano-geothermal area.

Geotourism Model of Ungaran Geothermal Area and Its Possible Hazard
Volcanogeothermal based geotourism in Ungaran area offers many touristic activities to the visitors.This tourism prospect carries geoheritage values and geological education values, is considered relatively new at this time.Based on geothermal conceptual model, this area can be divided into upflow zone and outflow zone (Figure 5).Upflow zone is characterized by higher terrain, fumarole, steaming ground, and acid sulphate water.Meanwhile, outflow zone is located in the lower area with travertine and bicarbonate-chloride spring manifestation.Using this approach, several possible hazards and risks are identified specifically in every zones.Exploring geothermal related environments is not always completely safe as there are a number of hazards that can occur, some of which are even quite unexpected.In conducting tours to locations with geothermal potential, there are many things that must be considered.The tourists will usually be very curious about geothermal manifestations such as fumaroles, steaming ground, and hot spring.However, the thing that also needs to be considered is the safety of tourists who will be threatened if unwanted things happen at the geothermal location.There are several hazards caused by geothermal manifestations and processes that can threaten the health and safety of tourists.Apart from the risk of serious burns from erupting hot springs, fumaroles which release extremely hot gases and vapors can also cause serious burns.Unexpected hydrothermal eruptions can also occur in any active geothermal field.Hot mud eruptions and steam eruptions can sometimes occur without any previous signs.This is caused by tourist sites located in geothermal fields with active seismic or volcanic activity.Other geothermal geotourism hazards also include the emission of gases such as H 2 S and CO 2 which can pose a serious threat, as these gases are potentially lethal within a few moments at higher concentrations.
Unfortunately, Ungaran volcano area is still lack of measure regarding of its possible hazards and risks.It is important to assure the sense of security of tourists when traveling.Geosite managers can add geographic paths, tour guides, and interpretive signs to increase tourist awareness of the potential hazards that exist in tourist sites.Ordinary visitors, who are not familiar with existing tourist sites will be greatly helped by the basic information provided by the manager.It also helps tourists navigate safely through the right zones.Managers can also provide pamphlets and brochures that can help tourists get to know tourist areas and locations that are quite important, such as evacuation routes, shelters, and also the nearest health facility.Tourists must have initial knowledge about the tourist environment in preparation for travel in a geothermal environment and at least visitors must also be prepared to deal with unexpected hazards that can occur at geothermal field locations.

Conclusions
Ungaran volcano and its surroundings have the potential to be developed as a volcano-geothermal based geotourism and geoedutourism.Total of six selected geosites which include geothermal manifestation sites and geomorphosite to view the volcanic landscape.After conducting the assessment using scientific and intrinsic approaches, educational value, economic value, conservation value and additional value, the results showed that five geosites met the assessment criteria.A constructed volcano-geothermal tourism model proposes several activities in this area based on geothermal upflow-outflow zone.Regarding to the possible hazards and risks, tourists must have proper understanding as well as appropriate management from the geosite managers.

Figure 1 .
Figure 1.Geological map of the research area according to[9]

5 - 5 -
10 km tourist facilities 1less than 5 km tourist facilities C Local products 0more than 10 km ftom the site existing tourist facilities 0.5 -5-10 km tourist facilities 1less than 5 km tourist facilities Conservation value A Actual threats and risks 0high on both natural and atrophic risks 0.5existing risks that can disturb the site 1low risks and almost no threats B Potential threats and risks 0high on both natural and atrophic risks 0.5existing risks that can disturb the site 1low risks and almost no threats C Current status of a site 0continuing destruction of the site 0.5the site destroyed, but now with management 1no destruction D Legislative protection 0no legislative protection 0.5existing proposal for legislative protection 1existing legislative protection Added value A Cultural value, presence of historical/ archaeological/ religious aspects related to the site 0no cultural features 0.5existing cultural features but without strong relation to abiotic features 1existing cultural features with the strong relations to abiotic features B Ecological values 0not important 0.5existing influence but not so important 1important influence of the geomorphologic feature on the ecologic feature C Aesthetic values, number of colours, structure of the space,