E203
Analysis of Earthquake-Induced Natech Events: A Monte Carlo-Markov Chain Methodology forStorage Tank Accident Sequence Modeling and Industrial Downtime Estimation(地震誘発ナテック現象の分析：貯蔵タンク事故シーケンスモデリング及び操業停止
時間推定のためのモンテカルロ・マルコフ連鎖手法)〇Peiyin JIANG・Ana Maria CRUZThis research focuses on earthquake-induced Natech accidents in chemical industrial parks, specificallytargeting the domino effects involving industrial storage tanks. Utilizing a Monte Carlo-Markov Chain method, thestudy analyzes the impacts of earthquakes on storage tanks and simulates subsequent domino effect scenarios. Themethodology incorporates factors such as thermal radiation, shockwave overpressure, and uses historical data todevelop recovery curves. The aim is to evaluate the probability of tank damage and the duration of industrial
downtime. Additionally, a case study of a storage tank farm at the Cosmo refinery in the Osaka Sakai area isconducted. This case focuses on understanding the implications of accident chain development on the outcomes oftank-related incidents. The study's approach provides insights into disaster resilience planning, emphasizing theimportance of dynamic consequence analysis for industrial facilities prone to earthquake-induced accidents.

1. Introduction

and the likelihood of their outcomes (Petak, 2002)

Technological accidents involving the release of

Downtime, as a measure of industrial accident impacts

hazardous materials triggered by natural hazards arefrom natural disasters, is a key aspect of industrial

known as Natech accidents (Cruz and Suarez, 2019).

resilience.

For instance, during the Great East Japan Earthquake
in 2011, severe fires and explosions at refineries in

2. Research Purpose
Numerous cases have shown that natural disasters

Sendai and Chiba led to a series of cascading incidents,

can cause significant damage to hazardous facilities,

known as the domino effects. Accidents involving

leading to severe consequences. This is particularly

dominolow-probability,

pertinent in earthquake-prone Japan, where studying

high-consequence incidents that can cause severe

the safety risks to industrial facilities posed bydamage to people, property, and the environment.

earthquakes is crucial. In the context of frequent

Despite the potential for escalation in Natech accidentsdisasters, Misuri et al. (2021) emphasize theinduced by earthquakes, the inherent domino effect isimportanceoften overlooked in plant engineering and design

triggered by natural disasters to enhance disasterprocesses. Dynamic consequence analysis offers apreparedness

rational approach for risk assessment and management

cascading accidents means that allowing disasterdue to the extensive and uncontrollable nature ofchains to develop can result in extremely serious

dominoofconsequences. Current studies on Natech events'

multi-physical fields in domino effect propagation candomino phenomena mainly focus on the transmission

enable a more accurate study of accident escalation.

mechanisms and probabilities of accidents between

Modeling or assessing the evolution of domino events

units. Although various methods and studies exist foris crucial for protecting chemical and process facilities

estimating infrastructure downtime, very few focus on

from the impacts of cascading accidents.

downtime caused by disasters and accidents.

effects

effects.

represent

Analyzing

thecoupling

In the context of earthquake hazard, resilient

Theofpurposeresearching

andofmitigation.

thisstudy

cascading
Theisaccidents

presence

toofinvestigate

systems or subsystems are defined by lower failure

earthquake-induced Natech accident chains and theirlikelihood and consequences. This includes thedynamic

probability of earthquakes, structural damage patterns,

development of an accident simulation model toconsequence

analysisthroughthequantify their probabilities and restoration times.

overpressure, combined with Probit models.

3. Methodology and model development
The dynamics of an earthquake related Natechd) Monte Carlo Sampling Simulation: We use a Monte

accident at an industrial park can follow the pathways as

scenarios under the given conditions and predict theshown in Fig. 1. The proposed model must then consider

disaster development timeline.

various issues as discussed below.

e) Post-Disaster Functionality Quantitative Model: Wea) Earthquake effects: This study uses an earthquake

develop a quantitative model to determine thealong the Nankai Trough in Japan as a reference

remaining

scenario for our case study, and the Next Generation

incorporating

Attenuation

prediction

consequences of earthquakes and domino cascadingequations (GMPE) to forecast seismic parameters fordisasters. We use HAZUS restoration curves andthe tanks. Furthermore, peak ground acceleration

Monte Carlo simulations to determine the restoration(PGA) and earthquake damage probability curves aretime distribution for the tank storage area.

used to determine the probability of tank damage.

f) Case Study: We use predicted PGA data for a major(NGA)groundmotion

Carlo sampling method to simulate all possible

post-disasterafunctionality

simplified

analysisoftanks,oftheearthquake on the Nankai Trough. The tank area forthe case study is selected from the Cosmo refinery in
the Osaka Sakai area, with tank layout data derived
from Google satellite maps and map measurements.

Fig. 1. The flow path of an earthquake-related Natech.

4. Results and conclusion
This study found that tank farm fire will last
2-3 days when the domino chain is allowed todevelop in the worst-case. Early termination of thedomino accident chain, such as through emergency
operations, would be effective in reducing
downtime. The model outputs are shown in Figs. 3
and 4 below.

Fig. 3. Simulation of gasoline storage tank domino
Fig. 2. Prediction of response spectrum in Osaka Area

accidents for one Natech scenario (PGA=0.3g, Terminal(top), and PGA (bottom left) and PGV (bottom right) for

Time=infinite).

a Nankai trough earthquake using NGA-Subduction
Ground-Motion Models.

b) Determining Initial Damage State: We use theHAZUS earthquake loss estimation method developedby FEMA, which provides vulnerability curves fordifferent structures, to determine the initial damage
state of tanks during an earthquake.
c)Transition Probability Analysis: We analyze theFig. 4. Analysis of Domino Effect Chain Termination

probability of tank state transitions based on escalation

Time on Tank Farm Restoration and Functionality

vectors, such as thermal radiation and shockwave(PGA=0.3g, Terminal Time≤30min).