Tephrochronology is a technique that uses discrete layers of tephra (i.e. volcanic ash) to create a chronological framework (Lowe 2011) useful to reconstruct the volcanic history of a given area. Its applications are numerous and there is great potential for expansion in Southeast Asia given the exceptional high density of volcanoes in this part of the world. The goal of this workshop is thus to review the current knowledge about tephrochronologic markers in the region — their composition and ages, to share findings and best practices, and to instigate region-wide collaboration.
The identification and correlation of tephra layers enables reconstruction of the number, timing and magnitude of eruptions that affected a given location. Improving our knowledge of volcanic eruption histories in Southeast Asia is important for a number of factors, the most obvious of which is regional hazards. Southeast Asia hosts ~750 volcanoes (70 of which have erupted in the past century) and is home to a population of ~600 Million. In Indonesia, for example, ~30% of the population lives within 30 km from a Holocene volcano. Another important factor is that Southeast Asian volcanoes are dominantly located close to the equator. Indeed, large volcanic eruptions that occur in equatorial to tropical regions and send ash into the stratosphere have particularly global impacts on climate because the ash and aerosols released propagate into both the northern and southern hemispheres.
143 volcanoes in Southeast Asia have been classified as Large Calderas (41) and Well-Plugged Stratocones (102) by Whelley & al (2015) and thus have or are likely to have produced large explosive eruptions with a Volcano Explosivity Index (VEI) of 5-8. Only 26 of such eruptions have known ages, spanning from 1.2 Ma to 1991 AD. Fewer have geochemical data that can be used for tephrostratigraphic correlations. Consequently, there is a knowledge gap that can be filled through field studies of these numerous volcanoes in combination with studies of marine, lacustrine, and other on-land sedimentary records.
Marine and lake sediments are fantastic archives of meteorological and geological processes (e.g. floods, landslides, volcanic eruptions, earthquakes) and environmental change (e.g. climate and land-use changes). For example, long term hydrological variations are recorded as changes in sedimentology, geochemistry and biological proxies in lacustrine and marine settings. Thus sediments from lakes and oceans provide high resolution palaeoenvironmental data for variations and interactions of the monsoons, El Nino Southern Oscillation, Indian Ocean Dipole, floods and droughts, and human activities. The identification and correlation of tephra layers in these archives enables linking, synchronizing and dating geological or environmental events that impact the local and regional ecology, human and climatic history. Filling the knowledge gap concerning volcanic eruption histories would thus contribute to further developing additional tephrochronologic markers that could help synchronize records over a larger spatial extent, at a greater temporal resolution, and over a greater period of time.
This workshop is an exciting opportunity to share knowledge and findings in order to start filling the identified knowledge gaps, and better define regional marker beds. It is also the opportunity to identify specific research targets that could be undertaken in collaboration, and action items to be revisited during a subsequent workshop. Lastly, it is a chance to train the new generation of Earth scientists and promote the use of tephrostratigraphy in this part of the world.
Please register online before
28 July 2019. Registration closed
Admission is free. Seats are limited, so hurry!
Financial Support (Students)
21 Jun 2019 - Closed
Poster Title Submission
Jun 2019 Closed
Online Registration Closes
28 Jul 2019 Closed
7 to 8 Aug 2019
Jointly organized by
Asian School of the Environment, NTU
Institute of Advanced Studies, NTU
Earth Observatory of Singapore
Assistant Professor Caroline Bouvet de Maisonneuve
National Research Foundation (NRF) Fellow
Nanyang Assistant Professor (NRF), Asian School of the Environment
Secretariat: Ms Nur Fairuz Binte Razali
Asian School of the Environment
Nanyang Technological University
50 Nanyang Avenue, Block N2-01C-63