Borobudur, a basin under volcanic influence: 361,000years BP to present

The geological evolution of Merapi volcano, Central Java, Indonesia

“…The oldest lavas of Old Merapi (Batulawang Series;Berthommier 1990;Camus et al 2000) are dated at~30 ka (K-Ar), which shows that Old Merapi is significantly older than inferred previously (Camus et al 2000;Newhall et al 2000). The oldest of only a small number of hitherto documented explosive eruptions of Old Merapi are younger than 11,792±90 14 C years BP, and some of these may have left deposits in the Borobudur basin (Gomez et al 2010). Our youngest age for a lava flow from the Somma-Merapi (4.8± 1.5 ka) indicates that the destruction of Old Merapi occurred after 4.8±1.5 ka.…”

“…In fact, it is possible that both edifices were active contemporaneously. In a recent study, Gomez et al (2010) discussed a potential link between volcanic rock samples from drill cores taken near Candi Borobudur 30 km west of Merapi and dated at~119 and 31 ka, respectively, and possible collapse events of Proto-Merapi in the sense of Newhall et al (2000) or the older Ancient Merapi stage (Camus et al 2000). With the new ages for Gunung Turgo and Gunung Plawangan presented in this study, a Merapi origin for these drill core samples from the Borobudur basin remains a possibility, although another volcanic source is equally feasible.…”

Boundary crossing and non‐linear theory in earth‐system sciences – a proof of concept based on tsunami and post‐eruption scenarios on Java Island, Indonesia

“…This first simulation has allowed us to compare simulation results with the observed data and once the right set of options was chosen we have run a second simulation introducing tsunami impacted areas on the southern coast (temporary water invasion, death of the present complex vegetation and return of a low vegetation); and a third simulation at Merapi Volcano, introducing modifications in land‐cover induced by a volcanic eruption. Considering present and past eruption activity at Merapi Volcano (Newhall et al , ; Camus et al , ; Gomez et al , ) the simulation of the eruption has been modelled by modifying the summit land‐cover into an andesitic ash cover (this modifies in the model the data of albedo, roughness, and soil humidity) without the introduction of a potential volcanic column or ejecta. The original land‐cover data has been downloaded from the USGS (United States Geological Survey), and the modified land‐covers were (1) a dry, light‐grey sandy material (to simulate the andesitic ash deposit) of 5 km radius from the summit of Merapi Volcano; and (2) a low ‘grassland’ type of vegetation in the simulated tsunami inundated area (up to 5 km in lowland).…”

“…Java low coasts and its position along the subduction zone of the Australian tectonic plate below the Indo‐European plate makes it a prime candidate for large tsunami and also volcanic eruptions. Indeed, Java Island is located about 40 km above the Benioff discontinuity, resulting in andesitique volcanoes producing explosive and dome collapse volcanism (Gomez et al , ). Active volcanoes appear like the spinal cord of Java Island (Figure ).…”

Environment, Trade and Society in Southeast Asia

“…van Bemmelen and some of his predecessors (Bemmelen 1956), based upon what was then known of the history of early Java. Given difficulties in precision of geological dating, more recent studies have tended not to question that original dating (Newhall et al 2000;Gomez et al 2010). 5 There appear to have been at least five separate flows of volcanic mud, possibly similar in the pattern to the more recent build-up of volcanic deposits on parts of the Caribbean island of Montserrat: the surface of each layer of lahar in central Java appears to have been exposed for long enough to become weathered, but most not for long enough for significant plant colonization and soil formation to have occurred (Newhall et al 2000: fig.…”