EGU2020-893
https://doi.org/10.5194/egusphere-egu2020-893
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

The Mt. Gamalama Instability in Generating Landslides in Ternate Island, Indonesia

Saaduddin Saaduddin1, Jurgen Neuberg1, Mark Thomas1, and Jon Hill2
Saaduddin Saaduddin et al.
  • 1University of Leeds, Institute of Geophysics and Tectonic, School of Earth and Environment, Leeds, United Kingdom of Great Britain and Northern Ireland (eessa@leeds.ac.uk)
  • 2University of York, Department of Environment and Geography, York, United Kingdom of Great Britain and Northern Ireland

Mt. Gamalama has a history of volcanic tsunamis that have occured in 1608 and 1840. Regarding its geomorphology, Mt. Gamalama has very steep flanks, and landslides entering the sea could be the potential mechanism of tsunami generation which could threaten the coastal population and submarine infrastructure in the vicinity of Mt. Gamalama.

The potential volumes and types of landslides are estimated by a study of the Mt. Gamalama instabilities using the Generalized Hoek-Brown failure criterion which is applied in Slide2D (Rocscience), a 2D slope stability program using limit equilibrium methods. This procedure will result in a so-called Factor of Safety or FoS which represents a value of the Mt. Gamalama slope stability level.

The critical FoS values ranging from 1.945 to 3.361 have been obtained for four sections i.e., north, south, west and east side of the Mt. Gamalama edifice and are considered in relatively stable condition. These values hold for a static condition only under the force of gravity and in the absence of any volcanic activities. The application of seismic coefficients of 0.103 and 0.658, magma pressure of 2-17 MPa, and various angles of a dyke intrusion decreases the Mt. Gamalama stability and might cause landslides. Based on posture parameter analysis of modeled landslides, the landslide volumes could reach 106 -109 m3. Furthermore, regarding the morphometric characteristic parameter analysis, the landslide mobility could enter the Molucca seaand generate tsunamis.

Keywords: Gamalama, volcanic instability, volcanic landlsides, volcanic tsuamis

How to cite: Saaduddin, S., Neuberg, J., Thomas, M., and Hill, J.: The Mt. Gamalama Instability in Generating Landslides in Ternate Island, Indonesia, EGU General Assembly 2020, Online, 4–8 May 2020, https://doi.org/10.5194/egusphere-egu2020-893, 2019