Geology, Archaeology, and Historical Studies of the Late 16th Century Plinian Eruption of Raung Volcano: A Potential Case for Disaster Geotourism in Ijen UNESCO Global Geopark, East Java, Indonesia

Abstract

The enigmatic major eruption in the late 16th century, believed to have originated from Raung, the most active stratovolcano in the Ijen UNESCO Global Geopark in East Java, Indonesia, has ignited significant debate among researchers and historians due to its profound impact on the region. This research aims to substantiate Raung as the likely source of the major eruption by integrating geological, archaeological, and historical data. This study synthesizes current findings and explores ongoing debates surrounding historical volcanic activities. Eruption parameters suggest that the late 16th century eruption exhibited a Plinian type, characterized by an explosive eruption column reaching the stratosphere, widespread pumiceous tephra fallout, and pyroclastic density current (PDC). Stratigraphic succession reveals that the eruption occurred in five phases, with deposits from 10 eruptive units. These deposits are mainly concentrated on the northwestern flank of Raung. Archaeological findings, historical records, and local legends converge to pinpoint the occurrence of this catastrophic event in the late 16th century. These diverse sources estimate that the eruption resulted in approximately 10,000 casualties, marking it as one of the most significant volcanic disasters in the past 500 years. The implications of this eruption extend beyond historical documentation, providing a critical case study for advancing disaster mitigation strategies through geotourism in the geopark area. Moreover, the eruption record outcrops identified in this study can be proposed as potential new geosites within the Ijen UNESCO Global Geopark, enhancing its educational and touristic value. We propose the Jebung Kidul, Alas Sumur, and Batu Sappar sites as potential disaster-based geosites, considering that these sites record the eruption process and preserve archaeological structures. This addition would not only commemorate the historical event but also promote awareness and preparedness for future volcanic activities in the region.

1. Introduction

1.1. Volcanic Eruption and Its Impact on Civilization

Volcanic eruptions represent some of the most potent natural disasters, capable of causing extensive destruction and severe consequences. The violent expulsion of molten rock, ash, and gases from the Earth’s interior can devastate landscapes, communities, and ecosystems [1]. The hazardous interplay of PDC, lava flows, ash fallout, and related phenomena such as tsunamis and mudslides render volcanic eruptions exceptionally perilous. Historically, these events have resulted in significant loss of life, climate alterations, and geographical transformations [2,3,4,5]. Several major volcanic eruptions have occurred worldwide, leading to numerous casualties and, in some cases, the extinction of civilizations [4,6,7,8,9]. An analysis of notable events, such as the eruptions of Vesuvius and Santorini in Europe and those in Indonesia, reveals their devastating impacts on historical societies. For example, the 79 A.D. eruption of Mt. Vesuvius obliterated the Roman cities of Pompeii, Herculaneum, and Stabiae, preserving a snapshot of Roman daily life [10]. The Minoan eruption of Santorini around 1600 BCE had extensive effects on the ancient Mediterranean world, including tsunamis that affected coastal civilizations and potentially contributed to the decline of the Minoans [11,12,13]. The 1883 eruption of Krakatoa in Indonesia resulted in widespread casualties and global climatic changes, while the 1815 eruption of Mount Tambora led to the “Year Without a Summer”, causing extensive crop failures and socio-economic disruptions [3,4,14,15,16,17,18]. The 13th century Samalas eruption on Lombok, Indonesia, is recognized as one of the largest volcanic events of the past millennium, affecting regional dynamics [19]. The Toba eruption on Sumatra around 74,000 years ago is considered one of the most catastrophic events in human history, forming the massive Lake Toba caldera and inducing a volcanic winter [15,20,21]. These eruptions not only resulted in loss of life and the disappearance of civilizations but also caused significant environmental damage.

Therefore, a deep understanding of the potential hazards posed by volcanic eruptions, particularly in geopark regions such as Indonesia, is essential for risk mitigation, effective emergency response planning, and the protection of communities and critical infrastructure from unforeseen natural disasters within these areas. Utilizing geological sites for disaster risk reduction education can effectively convey critical information about local hazards, as demonstrated in the Batur UNESCO Global Geopark, where geoheritage sites serve as educational platforms for volcanic disaster mitigation strategies [21]. The design of sustainable Geotourism Interpretation Centers in the Santa Elena Peninsula Geopark enhances local geoeducation, promoting awareness of geological and cultural heritage while improving tourist experiences [22]. Geotourism can play a pivotal role in promoting sustainable education and community development in volcanic geopark areas post-disaster by leveraging geoheritage for educational initiatives and community engagement. This multifaceted approach not only enhances disaster awareness but also fosters local economic resilience.

1.2. Debate on the Great Volcanic Disaster at the End of the 16th Century in East Java

During the Dutch colonial period, numerous significant volcanic eruptions in Indonesia were documented. The Dutch began recording volcanic activities in Indonesia as early as the 16th century. Consequently, volcanoes categorized as high-risk activity have been noted as active since at least 1600. These records provide a substantial understanding of the region’s volcanic activity history. Prominent eruptions, such as Krakatau in 1883 and Tambora in 1815, are well documented due to extensive historical records. In contrast, major eruptions prior to 1600 are difficult to verify unless evidenced by legends, inscriptions, or ancient manuscripts. For example, recent geological and archeological advancements have verified the Samalas eruption of 1257 [19,23] which was previously undocumented. Research is essential for uncovering evidence of significant eruptions before the 16th century, especially given Indonesia’s high volcanic activity. Several sources suggest that a major, mysterious eruption occurred in the Ijen UNESCO Global Geopark, East Java, Indonesia, around the end of the 16th century [24,25,26,27,28]. This event has been debated since the Dutch colonial period, with continuing discussions in Dutch texts about the specific volcano and its impact. Detailed accounts are scarce, as information during the Dutch colonial era was primarily derived from local narratives and Portuguese observations. One account reports a major volcanic eruption in 1586 [25], which resulted in 10,000 fatalities and extensive ash clouds. However, later research argues that the correct year should be 1593 due to a transcription error between Portuguese numerals 3 and 10 [26]. Additionally, Javanese chronicle data suggest 1584 as the eruption year [27]. The Journal of Mauritius likely intended to indicate 1593, contributing to ongoing confusion [25]. There is also debate over which volcano within the Ijen UNESCO Global Geopark experienced the eruption. Some sources attribute it to Mount Ringgit on the north coast, while others suggest a volcano in the central part of the island. Some subsequent studies support the Ringgit Volcano theory [28,29,30,31], while other research challenge it [29,30,32]. The investigation led by van Bemmelen in 1949 concluded that volcanic activity at Mount Ringgit ceased in the Pleistocene, leading to the hypothesis that the 16th century eruption originated from the active Raung Volcano to the south [25,33]. Confirmatory geological research is essential to validate that the late 16th century eruption originated from Raung and was a significant event in the Ijen UNESCO Global Geopark [34,35,36,37,38,39].

1.3. Geology and Eruptive History of Raung Volcano

Raung, located within the Quaternary volcanic zone on Java (Figure 1), is one of Indonesia’s most active stratovolcanoes [40]. Since the late 16th century, it has recorded over 60 eruptions, characterized by ash plumes, Strombolian activity, and lava flows. As the highest volcano in the Ijen UNESCO Global Geopark at +3344 m above sea level (masl), Raung is also the youngest and most active in the region. Its peak is devoid of vegetation and features a truncated cone shape, and there is a caldera with a diameter of 2.2 km × 1.7 km, along with a depression up to 500 m deep from the summit. Raung is situated within the Sunda Arc subduction system, characterized by an active continental margin from the subduction of the Indo-Australian Plate against fragments of continental crust believed to have originated from Gondwana [41]. It is the most recent volcanic cone in the Ijen Volcano Complex (Figure 2), overlying Tertiary sedimentary formations in a stratigraphic context [37,38]. The volcano produces PDC, pyroclastic fall, and basaltic lava [37,38], with a high potassium calc-alkaline magma series [38].

Recent significant activity at Raung includes eruptions in 2015, 2020, and 2022, which led to the closure of several airports due to ash dispersion. The 2015 eruption produced a large ash plume, disrupting air travel and impacting nearby communities. In response, the Indonesian Center for Volcanology and Geological Hazard Mitigation (CVGHM) raised Raung’s alert status to its highest level and advised residents and tourists to avoid the area. In 2020, Raung erupted with similar explosive characteristics, causing ash to drift over long distances and prompting flight cancellations. The 2022 eruption, while less intense, still resulted in significant ash emission. Raung’s complex stratovolcano structure, with its caldera and new active vents, allows for diverse eruptive behaviors. Raung’s volcanic activity ranges from moderate eruptions with a Volcanic Explosivity Index (VEI) of 1, characterized by frequent but relatively small events, to large, Plinian eruptions [42,43,44,45,46,47,48,49] with a VEI of 5, indicating a significant potential for widespread impact [38] (Figure 3). For instance, Strombolian eruptions, which are relatively mild and characterized by the ejection of incandescent cinders, lapilli, and lava bombs, frequently occur at Raung.

2. Methods

2.1. Field Observation

The search for evidence of significant volcanic eruptions required extensive field surveys to identify explosive eruption deposits around Raung Volcano. This effort was based on volcanic geological maps (Figure 2) and previous research [38]. The fieldwork conducted in 2023 involved the systematic collection of rock samples, measurement of layer thickness, and documentation of the horizontal and vertical dispersion of eruptive deposits based on lithofacies and componentry characteristics. Additionally, observations were made regarding possible archaeological findings related to the deposits. This data collection aimed to analyze patterns in the distribution of the eruptive deposits.

2.2. Stratigraphic Analysis

The stratigraphic analysis method of the eruptive products of a possible major eruption of Raung in the late 16th century involves correlating stratigraphic columns from various observation stations. This approach helps identify the distribution of PDC, fallout deposits, and lava deposits across different sections of the volcano, considering wind direction and, which topography influences the dispersal pattern of ash and pyroclastic material, and topography, which affects the lava flow paths and PDC.

2.3. Whole-Rock Geochemistry

Samples of fresh eruptive products were selected for geochemical analysis. A geochemical analysis of the major elements and trace elements was conducted using X-ray fluorescence (XRF) instruments at the Geological Survey Center in Bandung, Indonesia. Geochemically tested samples were taken from representative parts of each eruption phase. Juvenile material samples such as lava, bombs/blocks, scoria, and pumice from the volcanic products of this eruption were used to determine the rock types.

2.4. Archeological Findings and Historical Analysis

In addition to geological and volcanological studies, observations were also conducted to find archeological traces and search for supporting historical information such as scripts, legends, and myths. The investigation involved examining historical records, conducting excavations, and analyzing artifacts and structures related to the eruption in the late 16th century. By studying the remains of settlements, human artifacts, and cultural evidence, it was possible to assess the extent of the eruption’s impact on the local population, as well as the subsequent societal and environmental changes. The analysis of historical documents and accounts from the time of the eruption provided valuable insights into the experiences and responses of the affected communities. The bibliographic study methodology is conducted in this research by systematically analyzing historical documents, written accounts, and other textual sources. Furthermore, the examination of archaeological sites and cultural artifacts provides critical insights into the aftermath of Raung’s catastrophic eruptions, offering a deeper understanding of how communities coped with and recovered from such catastrophic events.

3. Results and Analysis

3.1. Deposit Stratigraphy

A stratigraphic analysis of over 20 observation stations identified and then categorized eruption products into 10 eruptive units, further grouped into 5 eruption phases (Figure 4). Eruptive deposits preserve a sequence of several phases of explosive eruptions. All eruptive units exhibit contacts that are uninterrupted by soil layers, indicating the absence of significant time gaps during the deposition of these units. Soil layers are only found beneath the earliest unit (unit A) and above the latest unit (unit J). Units A, C, and F consist of pyroclastic fall deposits rich in pumice, with an increasing lithic content towards the top. Unit D’s PDC and unit F’s fallout deposits are separated by basaltic lava in the Batu Sappar site, which has complete stratigraphic outcrops for this eruption (Figure 5), consistent with previous research [37,38,50,51,52,53,54,55]. These pyroclastic fall units alternate with the PDC deposits of units B, C, and G concentrated on the northwest flank of Raung (Figure 6). Units H, I, and J represent the uppermost units in the stratigraphic sequence.

Unit A consists of a well-sorted white pumice-rich layer (3–5 cm thick). Unit B comprises a massive gray layer, poorly sorted, containing pumice-rich lapilli-sized fragments (30%) within a coarse ash matrix (70%) composed of pumice, scoria, and lithics. Units A and B are widely distributed on the west-northwestern slopes of Raung, covering both low and high topography and thickening towards the vent (Figure 5). In contrast, unit C is a well-sorted yellow pumice-rich layer (4–10 cm thick). Unit D (Figure 6) is characterized by a massive yellowish-brown layer, poorly sorted, with block-lapilli-sized fragments (40%) rich in pumice and scoria, within a coarse ash matrix (60%) composed of pumice, scoria, and lithics. Unit D is distributed along the northwest–southeast-oriented valleys between Mount Suket and Mount Gadung (Figure 7). Unit E is basaltic lava, dark gray in color, with a porphyritic texture, containing phenocrysts of plagioclase, olivine, and pyroxene embedded in a dark gray aphanitic groundmass. It exhibits autobrecciation structures at the top and bottom, with thermal alteration effects at the contact with unit D below and unit F above. Unit F is a lithic-rich brown layer (5–10 cm thick), angular, and well sorted. Unit G is a massive dark gray layer, poorly sorted, containing lithic-rich block-sized fragments (80%) within a lapilli-coarse ash matrix (20%) composed of lithics, scoria, and pumice. Unit G is overlain by thin layers of scoria-rich ash. Units F, G, and H have a widespread distribution, extending from the north and west to the south of Raung. Meanwhile, unit H is a light gray lithic-rich layer, and unit J consists of lahar deposits composed of a mixture of materials from previous eruptions [56,57] (Figure 6).

3.2. Correlation of Deposits

Stratigraphic correlation involved linking the stratigraphic columns from each observation station, with each location analyzed in detail. From this correlation, three cross-sections were created, focusing on the distribution of main deposits influenced by wind direction. The first cross-section, oriented NE-SW and cutting across wind direction (Figure 7), reveals that PDC deposits from units C, D, and G are concentrated in valleys on the northwest slopes of Raung, between Mount Suket and Mount Gadung (Figure 7). In contrast, pyroclastic fall deposits from units A, C, and F are well preserved in the southwestern area on the slopes of Mount Gadung and the northeastern slopes of Mount Suket. Brick findings in Ledokombo (LDK station), located in the southwest, are covered by pyroclastic fall deposits from units A, C, and F, whereas bricks in Alas Sumur, in the northwest, are covered by PDC deposits from unit G [52]. The second cross-section runs parallel to the wind direction, oriented NW-SE (Figure 8). This section shows that the proximal area is dominated by PDC deposits from unit G, which overlie the lava of unit E. Pyroclastic fall deposits are rare in this section. The third cross-section also follows the wind direction, extending from the northwest to the southeast before continuing south against the wind (Figure 9). In this section, only PDC deposits from units D and G are present, with no pyroclastic fall deposits or lava observed. In the distal part to the northwest, pyroclastic fall deposits from units A, C, F, and H are found, with unit H lying atop the unevenly distributed PDC deposits from unit G. The thickness of both the fallout and flow deposits decreases with distance from the scoria eruption center. The lower part consists of pumice-rich fallout deposits interlayered with PDC deposits formed from the collapse of the eruption column. The middle section comprises lava flows likely formed during the effusive phase and dome formation. The upper portion of the lava features fallout deposits containing abundant lava fragments, followed by PDC during the climax phase of the eruption, capped by a thin layer of widely distributed fallout deposits and lahars in the distal areas.

3.3. Geochemical Composition

The type of volcanic rock in the eruptive products of the Raung eruption is categorized based on the total alkali and silica content classification [58,59]. The whole-rock geochemistry analysis of samples from each phase reveals a decrease in SiO₂ content from phase 1 to the climactic phase 4, with the first phase producing dacite and the final phase yielding basaltic-trachyandesite (Figure 10). The alkali content is slightly higher compared to Old Raung and Ijen Caldera products, indicating distinct geochemical evolution across the eruption phases.

3.4. Archeological Discoveries

Recent archaeological investigations have provided significant insights into ancient civilizations buried by volcanic deposits on the Raung flank. Our research revisited the site in Ledokombo (LDK station) (Figure 11), where an ancient brick structure was first uncovered in 2018 at Padasan Hamlet, Ledokombo Village, Jember Regency. This structure, consisting of walls built with bricks measuring 30–42 cm in length and 15–22 cm in width, was found beneath three layers of fallout deposits in the southwest region. We conducted an excavation in collaboration with the Tourism and Culture Department of Bondowoso Government and the East Java Cultural Heritage Conservation Center, in Alas Sumur Village (ALS station), Pujer, Bondowoso Regency, revealed an ancient structure with nine layers of red bricks located 5 m below PDC deposits (Figure 11). These bricks, measuring 30 cm by 17 cm by 5 cm, are dated to the classical Hindu kingdom period of Java, around the 16th century [60].

Our observations in Bataan Hamlet, Jebung Kidul Village (JBK station), Tlogosari District, on Raung’s northern slope added new findings, including more ancient bricks, pottery and ceramic shards, and bones, although the origin of the bones remains unconfirmed. The brick structure at the Jebung Kidul site is the largest and most extensive one we have discovered. The pottery and ceramic shards, attributed to the Ming Dynasty (14th–16th centuries), along with green chalcedony porcelain fragments from the Yuan Dynasty (13th–14th centuries) and white porcelain from the late Song Dynasty (12th–13th centuries), suggest that a significant settlement was affected by a catastrophic event. The combination of these findings, particularly the archaeological layers and artifacts, indicates a major volcanic eruption around the late 16th century, specifically in 1593, attributed to Raung Volcano. This covered archaeological structure offers crucial evidence that the Raung eruption in the past caused a major disaster in the region. These discoveries contribute a significant perspective to the debate on large volcanic eruptions in Eastern Java during that century and underscore the potential for incorporating these sites into a geotourism route, offering a comprehensive understanding of volcanic impacts on historical human settlements.

3.5. Historical Interpretation

3.5.1. Bibliography Analysis

We conducted a bibliography analysis of narratives, books, and scripts that document the events of the Raung eruption. This analysis aimed to extract detailed accounts and interpretations of the eruption, providing a historical context that complements our geological and archeological findings. By examining these sources, we sought to enhance our understanding of the eruption’s impact and its historical significance. Several historical texts mention the eruption, but only a few provide a detailed description of the eruption process (Figure 12). The remnants of this eruption are also documented in ancient manuscripts such as the Babad Tawangalun [46], depicting the occurrence of a major eruption from Raung Volcano [61]. Initially, Dutch explorers suspected that this eruption occurred in 1586 and originated from Gunung Ringgit [47]. However, it was later confirmed that Gunung Ringgit had been extinct since the Pliocene, and the most likely active volcano responsible for the major eruption was Raung. The observational account from the Portoguese stands as the most comprehensive, offering a detailed narrative of the late 16th century eruption [42]. The Portuguese manuscript holds more credibility because, during the eruption, Portuguese sailors had already reached the eastern tip of Java Island compared to the Dutch, who arrived in 1596. Caminha’s Portuguese quote in 1807 reads, “Anno de 1593 soccedeo hum caso espantoso em Panaruca digno de lembrança E foy que no alto dos Montes e alterosos Picos arre bentarão hứas minas de enxofre com tão grande estrondo que totalmente atemorisou a toda aquella gente Panarucana porque se não ou uia outra cousa por espaço de oito dias mais que hús sonidos como trouões e rayos de fogo despedie dos daquelles Montes chamados os Gunos de Panaruca e choueo em todos aquelles oito dias tanta copia de cinza quero dizer ouve tanta cinza dos ares que todos os campos segment segment e praças e lugares publicos e tectos dos telhados das casas estavam tao entulhados de cinza que não ouve poder passar å gente pollos caminhos porque também fazia tão grandes treuas é escuridade por causa de estar o ar turvo e cinzento ou cheio de cinza que totalmente parecia noite”. The translated quote in english is, “In 1593, a terrible event occurred, which is worth remembering. The incident occurred at the top of a mountain that contains sulfur. The mountain exploded with such a huge roar that it really scared everyone in Panarukan City. For eight days, nothing was seen except roars and fiery fountains erupting from the top of the mountain, which is called ‘Mount of Panarukan’, and it rained for those eight days so much ash—I mean, so much ash fell from the air, blanketing the fields, streets, squares, public places, and roofs of houses, so covered with ashes that we can’t even walk through them. People saw that the streets were very dark because the air was filled with wisps of gray clouds that really looked like night”. The author of [43] later interpreted that the “burning mountain” and “flying rock” reaching Panarukan might be related to a massive ash fall. It was even suggested that the top of the mountain collapsed after the eruption ceased. The author of [26] noted that this eruption, as indicated by the account of Thomas Cavendish, a British sailor who anchored in Teluk Pangpang near ancient Blambangan east of Raung from 1 to 16 March 1588, only damaged Panarukan in the north. Cavendish did not mention volcanic eruptions at all.

Several decades later, in the 1980s, this eruption was recorded as one of the major eruptions of the 16th century [34], with an estimated VEI of 5 [10]. Some researchers already conducted a simple bibliographic study, gathering historical records about the eruption that highlighted the significance of the event [35]. Subsequently, several layers of polar ice cores containing volcanic material were discovered, some of which showed anomalies in sulfate (SO₄) content [53]. Volcanic glass-rich layers from the late 16th century, including one from 1593, were identified, but the exact volcano from which the volcanic material originated remained unknown [36]. Later, detailed sulfate measurements were conducted on ice cores from Siple and Dyer Stations in Antarctica, covering intervals from the 14th to the 20th century, and sulfate anomalies were found for the year 1593 [53]. The late 16th century eruption of Raung is believed to have contributed to the cooling in Europe at the end of the 16th century, commonly known as the “Little Ice Age” [54,55]. Other impacts include the onset of Alpine glacier melting from 1593 to 1630 [56,57]. This eruption is also estimated to have contributed to crop failures in Russia at the end of the 16th century and drought and famine in Tonkin, Vietnam, and there are indications of below-average vegetation growth, as evidenced by the narrowing tree ring widths from the forests of Java at that time [47,58]. A recent analysis aligns with the report of the Global Volcanism Program (GVP), which categorized the eruption as VEI = 5 in 1593, indicating that the eruption was quite significantly big.

3.5.2. Legends and Myths

We collected information on legends and myths through a combination of previous research and interviews with residents. This process involved reviewing historical accounts and folklore, as well as conducting direct conversations with community members to gather firsthand narratives. This approach provided a comprehensive understanding of the cultural and mythological context surrounding the volcanic events in the region. The powerful eruption of Raung has left a lasting impact on the people, inspiring myths and legends that continue to endure. Among these narratives, the Chronicle of Tawangalun recounts the legend of the white tiger, a tale widely recognized in the region. According to this story, the summit of Raung is considered the focal point of the White Tiger Kingdom, serving as the throne of Prince Tawangalun [61]. A renowned folklore detailing the conflict between Damarwulan and Minakjinggo finds its backdrop in the Blambangan Kingdom, situated on the flank of Raung. The Blambangan Kingdom was a prominent Javanese kingdom located in the southeastern part of Java, Indonesia, during the 13th to 18th centuries. Known for its strategic coastal position and rich cultural heritage, the kingdom played a crucial role in regional trade and politics [62]. It was characterized by its unique blend of Javanese and Balinese influences, evident in its art, architecture, and religious practices [44]. Historical records also indicate a governmental vacuum and the relocation of the Blambangan Kingdom’s capital to the southern flank of Raung in the late 16th to 17th centuries [44], potentially linked to the crisis arising from this eruption. Inhabitants residing on the northern and western slopes even hold the belief that lava flows, coursing through several rivers, represent spilled blood from the war [45]. Another geological tale associated with the collapse of a section of Raung’s summit revolves around the account of Bima’s encounter with Empu. The story tells of a blacksmith (Empu) living at the top of Raung, toiling tirelessly day and night until sparks flew to where Dewa Bima was meditating. Expressing his wrath, the deity ultimately destroyed the forge (at Raung’s summit), causing fragments to scatter into the South Sea (Indian Ocean), forming a series of hills. These narratives, originating around 500 years ago, indicate that ancient beliefs depicted Raung as a conical volcano with a prominent peak prior to its disappearance or collapse due to likely significant volcanic activity. Major natural events added to the trauma experienced by the Blambangan people. Legends and folklore about the eruption of Raung emerged in the late 16th century, supported by the existence of the Raung caldera formed in historical times, witnessed by inhabitants of the Blambangan Kingdom.

3.6. Potential Geosite for Disaster Geotourism

We are employing a matrix analysis to identify and evaluate key potential sites for geotourism near Raung flank that records the eruption (Figure 13). This approach utilizes a geosite matrix to categorize sites based on geological significance, archeological findings, and historical data. By assessing these factors, the matrix analysis provides a comprehensive framework for selecting sites that offer both educational value regarding geological features and potential function for geopark development. This method ensures that geotourism development aligns with sustainable practices and effectively communicates the associated risks and benefits to visitors. Based on geological observations of Raung’s eruptions and archeological and historical data, there is significant potential to develop disaster-based geotourism in the Ijen UNESCO Global Geopark. Leveraging the geological impact of Raung’s eruptions, along with cultural and historical insights, could enhance the geotourism value of the region. Establishing disaster-focused geotourism routes would not only provide educational opportunities about volcanic hazards but also integrate local historical narratives and archeological findings, thereby enriching the overall geotourism experience and adding value to the geopark. Jebung Kidul, Alas Sumur, and Batu Sappar exhibit considerable potential for development into disaster-based geotourism sites within the Ijen UNESCO Global Geopark (Figure 14). Jebung Kidul’s extensive brick structure complex, covered by laharic deposits from Raung’s eruptions (Figure 11), offers a tangible record of pyroclastic and laharic flow impacts, providing educational insights into volcanic hazard management. This site can be utilized for conservation, education, research, and geotourism activities due to its extensive area and the sizable structure of its volcanic rocks. Alas Sumur, situated beneath a thick PDC unit, represents the climactic phase of Raung’s eruption (Figure 11), highlighting the scale and intensity of volcanic activity through its preserved geological deposits. The site is suitable for conservation, educational, and geotourism purposes, as it can offer a disaster diorama illustrating the burial of a civilization by PDC from unit G. Batu Sappar, with its basaltic lava flows from unit E and its cultural significance, further enhances the region’s geotourism potential by illustrating the effusive eruption phase and integrating local cultural narratives. The adjacent waterfall, documenting multiple eruption units, complements the geological story by offering a continuous record of volcanic processes. It is also valuable for research, as it records the transition from explosive to effusive eruption and exposes nearly the entire eruption sequence. Additionally, the site is appropriate for geotourism related to lava flows. These proposed geosites are easily accessible, as they are located not far from existing pathways and villages, just about a 30 min drive from the city of Bondowoso (Figure 14). Incorporating these sites into geotourism routes offers educational insights into volcanic hazards while preserving the archaeological and historical value.

The design of the additional geosite is centered around the eruption stages of the Raung, providing a sequential route that allows visitors to understand the eruption process from its initiation (phase 1) to its conclusion (phase 5). Each stage of the eruption is represented by specific geosites that showcase key volcanic features and deposits, reflecting the transition from initial explosive activity to the final effusive phases. This approach offers a comprehensive understanding of the eruption’s progression, highlighting the changes in eruptive dynamics over time. In addition to illustrating the volcanic processes, the route also connects these stages to the impacts on local civilizations. For example, geosites associated with later phases of the eruption reveal evidence of buried structures, offering a glimpse into how ancient communities were affected by volcanic events. The integration of geosites documenting volcanic disaster events into the geotourism framework of the Ijen UNESCO Global Geopark presents a valuable opportunity to expand and diversify tourism activities, particularly within the Raung flank, which currently has a limited number of sites (Figure 14). By incorporating sites such as Jebung Kidul, Alas Sumur, and Batu Sappar, each representing different aspects of past volcanic disasters into the geotourism route, visitors can gain a deeper understanding of the impact of volcanic events on both the environment and human civilization (Figure 14). The expanded route provides a more comprehensive geotourism experience by integrating observations of prominent geosites, such as the Ijen Caldera complex and the Kawah Ijen blue fire, with an emphasis on the historical and geological significance of disaster events. By incorporating disaster-related sites into the existing geosites, the route broadens the scope of geotourism within the Geopark.

4. Discussion

4.1. Potential Burial of an Ancient Civilization

The eruption of a large volcano can lead to the burial of civilizations, as seen with Pompeii in Italy [10] and Ilopango, El Salvador [63]. Thick layers of volcanic ash and debris can entomb entire communities, preserving them for centuries. Archaeological evidence, such as the discovery of the Samalas artifact in Indonesia, highlights the magnitude of volcanic events. This artifact, linked to the 13th century Samalas eruption, underscores the impact of such disasters [19]. In eastern Java, the disappearance of the Blambangan kingdom [44], located near Raung, may be attributed to volcanic eruptions (Figure 15). The region’s population dynamics, with Javanese communities surviving to the south and Madura communities to the north and west, align with the direction of eruption deposits. The eruption of Raung in the late 16th century likely resulted in the destruction of nearby civilization, as evidenced by the discovery of brick structures only in certain areas to the north and west flank of Raung (Figure 11). Most of the population at that time is presumed to have disappeared, with only a small portion surviving. When looking at historical data, the figure of 10.000 casualties is not a small number in the context of a natural disaster event; this undoubtedly has an extraordinary impact on civilization [32]. Consequently, in the early 16th century, when the Dutch first arrived in Indonesia, they brought Madura people communities to work as plantation laborers in the northern and western areas of Raung, now inhabited by the Madura people [23]. This supports the hypothesis that the eruption of Raung in late 16th century was a key factor in the burial or extinction of the ancient civilization in the northern region of Raung, currently inhabited by the Madura people. Meanwhile, the unaffected indigenous population can be observed as the Osing ethnic group and some Javanese communities in the southern region, around Banyuwangi, to parts of Jember [23,44]. Archeological findings buried under volcanic layers suggest powerful eruptions, supporting the theory and offering strong proof of the downfall of an ancient civilization near Raung in the late 16th century. The demographic changes following the major late 16th century eruption have fueled ongoing debate among the local community and Dutch colonial settlers [44].

4.2. Comparison with Other Eruptions

The late 16th century eruption of Raung with VEI = 5 [38], while not as globally renowned as some of history’s most significant volcanic events, holds considerable regional and historical importance. Unlike the eruption of Vesuvius in 79 A.D. [4], which famously buried the cities of Pompeii and Herculaneum, or the Tambora eruption in 1815 [17,50], which led to the “Year Without a Summer” and global climate alterations, the Raung eruption is relatively less documented on the world stage. Similarly, the explosive events of Krakatau in 1883 [3], Samalas in 1257 [19], and Pinatubo in 1991 [51] left lasting marks in geological history, with Krakatau’s eruption being one of the loudest ever recorded and the latter two affecting global temperatures temporarily. The late 16th century Raung eruption results in a caldera size of 2.5 km, similar to the 1991 eruption of Mount Pinatubo in the Philippines. This eruption is among the largest historical eruptions in the eastern Sunda Arc in terms of impact on civilization, alongside Tambora in 1815 and Samalas in 1257. The late 16th century Raung eruption, though not widely known globally, had a profound impact on local Blambangan Kingdom folklore and left geological evidence that now attracts archaeological interest. It highlights Earth’s dynamic geological processes and the varied effects of volcanic events on regional societies and the environment.

4.3. Implications for Disaster Preparedness and Geotourism Potential

Ijen UNESCO Global Geopark is a volcanic geopark in Indonesia, established in 2018, that highlight the blue fire phenomena in Kawah Ijen volcano as main geosites. However, apart from geosites that offer beautiful geological phenomena, volcanic disasters in this area also need to be highlighted. The late 16th century Raung eruption serves as a compelling case for disaster geotourism within the Ijen UNESCO Global Geopark. The eruption’s impact on local populations, including demographic shifts and societal changes, highlights the long-term effects of natural disasters, which can be integrated into geotourism initiatives. By examining the historical consequences of the eruption, the Geopark Managerial Board can develop geosites that educate visitors about the resilience and adaptations of communities affected by volcanic events. Incorporating disaster geotourism sites into the geopark not only enriches the visitor experience but also enhances public understanding of volcanic hazards and their historical impacts. This approach allows the Geopark Managerial Board to showcase the interconnectedness of geological processes and human history, offering valuable lessons for contemporary disaster preparedness and mitigation [21]. Through responsible geotourism, the Geopark Managerial Board can provide educational opportunities that foster a deeper appreciation of both the region’s geological heritage and its cultural resilience. The disaster case of the Raung eruption is a good example for the development of geotourism in the disaster sector for past disaster education [21,22]. Therefore, this study recommends adding new geosites to the Ijen UNESCO Global Geopark in the next UNESCO revalidation stage. These sites include the Jebung Kidul Geosite, which records an ancient brick complex buried by a lahar deposit; the Alas Sumur Geosite, which features ancient bricks buried by thick PDC; and the Batu Sappar Geosite, which records lava flow and the complete stratigraphy of the major Raung eruption. This integration of new geosites will enhance the educational and cultural value of the geopark, making it a more comprehensive resource for understanding and appreciating the region’s volcanic history and its impacts on human civilization. This disaster-based geotourism will also promote disaster preparedness through education, research, and tourism activities for local communities [21].

5. Conclusions

Based on this study, it can be concluded that the major volcanic eruption in the late 16th century originated from Raung. This eruption, one of the significant volcanic events that have not been well studied or documented previously, had a profound impact on local civilization. The Plinian eruption of Raung in the late 16th century, with a VEI of 5, produced a substantial amount of volcanic material rich in pumice, predominantly directed towards the northern, northwest, and western flanks and comprises 10 deposit units divided into 5 eruption phases. This eruption has covered numerous archaeological sites on the same flank area, subsequently indicating evidence of a significant disaster in the region’s past. The eruption also resulted in demographic shifts, cultural adaptations, and potentially the extinction of the ancient Blambangan Kingdom. Comparing this event with other historically significant volcanic eruptions highlights its regional and historical implications, providing insights into the diverse impacts of volcanic activity and demonstrating how past events can inform contemporary disaster geotourism strategies.

The investigation into the late 16th century Raung eruption highlights its potential for developing new geosites related to volcanic disasters within the Ijen UNESCO Global Geopark. Historical and geological insights from this eruption can enhance the Geopark’s significance and diversity. We propose three sites, namely Jebung Kidul, Alas Sumur, and Batu Sappar, that document eruption phases and interactions with archaeological materials like bricks and pottery. These sites can serve as a disaster diorama, promoting disaster geotourism and providing valuable educational opportunities about the region’s volcanic history and its effects on local communities. By integrating disaster geotourism, the geopark can raise awareness of volcanic hazards, support disaster mitigation efforts, and foster community resilience while enhancing appreciation for geological heritage.