Optimal Design for Placements of Tsunami Observing Systems to Accurately Characterize the Inducing Earthquake

Abstract

Recently, there are numerous tsunami observation networks deployed in several major tsunamigenic regions. However, guidance on where to optimally place the measurement devices is limited. This study presents a methodological approach to select strategic observation locations for the purpose of tsunami source characterizations, particularly in terms of the fault slip distribution. Initially, we identify favorable locations and determine the initial number of observations. These locations are selected based on extrema of empirical orthogonal function (EOF) spatial modes. To further improve the accuracy, we apply an optimization algorithm called a mesh adaptive direct search to remove redundant measurement locations from the EOF-generated points. We test the proposed approach using multiple hypothetical tsunami sources around the Nankai Trough, Japan. The results suggest that the optimized observation points can produce more accurate fault slip estimates with considerably less number of observations compared to the existing tsunami observation networks.

Potential deployment of offshore bottom pressure gauges and adoption of data assimilation for tsunami warning system in the western Mediterranean Sea

“…7 Comparison of the observations (black lines), simulation (blue lines) and forecasted (data assimilation; red lines) waveforms at four PoIs for the third (a; three OBPGs) and fourth (b; two OBPGs) scenarios. The time window for assimilation is 20 min (dashed vertical line) strike, epicenter) combined with numerous OBPGs arrangements (number, alignment, spacing) (Mulia et al 2017(Mulia et al , 2019 are necessary to determine the optimum OBPGs network design for the WMB which can address tsunami threats from all four tsunamigenic zones in this basin. This was out of the scope of this study because we here focused on a single case study considering one tsunamigenic zone (i.e., NAC) and one real tsunami event (i.e., the May 2003 tsunami).…”

An Optimized Array Configuration of Tsunami Observation Network Off Southern Java, Indonesia

“…Spillane et al () introduced an optimization but for a more global observational scale. In our previous study (Mulia, Gusman, et al, ), we applied an optimization for tsunameter placements suitable for near‐field events. The resulted observation network is better than both hypothetical equidistant observation points and the existing observing systems around the Nankai Trough.…”

“…Previous studies have proposed a variety of methods to design tsunami observation networks applied to several tsunamigenic regions (An et al, ; Mulia, Gusman, et al, ; Omira et al, ; Schindelé et al, ). In this study, we develop a design for the cost‐effective placement of tsunameters around the southern Java region.…”

Tsunami Data Assimilation of Cabled Ocean Bottom Pressure Records for the 2015 Torishima Volcanic Tsunami Earthquake

“…Wang et al () conducted a synthetic experiment to demonstrate that these observational systems were able to forecast the tsunami waveforms at Shikoku Island by tsunami data assimilation approach. Similarly, in addition to the synthetic data at DONET systems, Mulia et al () applied the tsunami data assimilation to the virtual tsunami observations by ship height positioning around the Nankai region. In this paper, we assimilated the actual tsunami data recorded at ocean bottom pressure gauges from the 2015 Torishima earthquake and retroactively forecasted the coastal tsunami arrival times and amplitude.…”