Product catalogue
Tsunami variability from uncalibrated stochastic earthquake models: Tests against deep ocean observations 2006-2016
This study tests three models for generating stochastic earthquake-tsunami scenarios on subduction zones by comparison with deep ocean observations from 18 tsunamis in 2006-2016. It focusses on the capacity of uncalibrated models to generate a realistic distribution of hypothetical tsunamis, assuming the earthquake location, magnitude and subduction interface geometry are approximately known, while details of the rupture area and slip distribution are unknown.
<p>Modelling problems like this arise in tsunami hazard assessment, and when using historical and paleo-tsunami observations to study pre-instrumental earthquakes. Tsunamis show significant variability depending on their parent earthquake's properties, and it is important that this is realistically represented in stochastic tsunami scenarios. To clarify which aspects of earthquake variability should be represented, three scenario generation approaches with increasing complexity are tested: a simple fixed-area-uniform-slip model with earthquake area and slip deterministically related to moment magnitude; a variable-area-uniform-slip model which accounts for earthquake area variability; and a heterogeneous-slip model which accounts for both earthquake area variability and slip heterogeneity. The models are tested using deep-ocean tsunami time-series from 18 events (2006-2016) with moment magnitude $M_{w} > 7.7$.
<p>For each model and each observed event a `corresponding family of model scenarios' is generated which includes random scenarios with earthquake location and magnitude similar to the observation, with no additional calibration. For an ideal model (which perfectly characterises the variability of tsunamis) the 18 observed events should appear like a random sample of size 18, created by taking one draw from each of the 18 `corresponding family of model scenarios'. This idea facilitates the development of statistical approaches to test the models.
<p>Firstly a goodness-of-fit criterion is developed to identify random scenarios `most similar' to the observed tsunamis, and assess the capacity of different models to produce good-fitting scenarios. Both the heterogeneous-slip and variable-area-uniform-slip models show similar capacity to generate tsunamis similar to observations, while the fixed-area-uniform-slip model performs much more poorly in some cases. Secondly the observed tsunami stage ranges are tested for consistency with the null hypothesis that they were randomly generated by the model. The null hypothesis cannot be rejected for the
heterogeneous-slip model, whereas both uniform-slip models exhibit a statistically significant tendency to produce small tsunamis too often.
<p>Finally the statistical properties of random earthquake scenarios are compared against those earthquake scenarios that best fit the observations. For the variable-area-uniform-slip models the best-fitting model scenarios have higher slip on average than the random scenarios, highlighting biases in this model. Such biases are not evident in the heterogeneous-slip model. The techniques developed in this study can be applied to test random tsunami scenario generation techniques, identify and partially correct their biases, and provide better justification for their use in applications.
Simple
Identification info
- Date (Creation)
- 2018-12-04T00:00:00
- Date (Publication)
- 2019-07-03T23:32:15
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/124287
- Cited responsible party
-
Role Organisation / Individual Name Details Author Davies, G.
- Purpose
-
Communicate Probabilistic Tsunami Hazard Assessment Results
- Status
- Completed
- Point of contact
-
Role Organisation / Individual Name Details Point of contact Davies, G.
- Spatial representation type
- Topic category
-
- Geoscientific information
Extent
Extent
))
- Maintenance and update frequency
- As needed
Resource format
- Title
-
Product data repository: Various Formats
- Website
-
Data Store directory containing the digital product files
Data Store directory containing one or more files, possibly in a variety of formats, accessible to Geoscience Australia staff only for internal purposes
- Keywords
-
-
tsunami hazard
-
- theme.ANZRC Fields of Research.rdf
-
-
EARTH SCIENCES
-
- Keywords
-
-
Published_External
-
Resource constraints
- Title
-
Creative Commons Attribution 4.0 International Licence
- Alternate title
-
CC-BY
- Edition
-
4.0
- Access constraints
- License
- Use constraints
- License
Resource constraints
- Title
-
Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
Associated resource
- Association Type
- Cross reference
- Title
-
The 2018 Australian Probabilistic Tsunami Hazard Assessment
- Citation identifier
- 122789
- Citation identifier
- fd1533d2-b176-45b1-9d40-5936aaef7d6f
Associated resource
- Association Type
- Was informed by
- Title
-
The 2018 Australian Probabilistic Tsunami Hazard Assessment
- Citation identifier
- 122789
- Citation identifier
- fd1533d2-b176-45b1-9d40-5936aaef7d6f
Associated resource
- Association Type
- Was generated by
- Title
-
PTHA18 source-code repository and data access scripts
- Citation identifier
- 83958
- Citation identifier
- 1da13c50-0815-334e-e053-12a3070abfaa
Associated resource
- Association Type
- Was generated by
- Title
-
2018 Australian Probabilistic Tsunami Hazard Assessment Results
- Citation identifier
- 122796
- Citation identifier
- 11af3b85-b6b2-4e77-9e89-a18041d8b083
- Language
- English
- Character encoding
- UTF8
Distribution Information
- Distributor contact
-
Role Organisation / Individual Name Details Distributor Commonwealth of Australia (Geoscience Australia)
Voice
- OnLine resource
-
Link to Journal article
Link to Journal article
- Distribution format
-
-
html
-
Resource lineage
- Statement
-
Developed by GA as part of the National Probabilistic Tsunami Hazard Assessment
- Hierarchy level
- Document
Metadata constraints
- Title
-
Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
Metadata
- Metadata identifier
-
urn:uuid/096dfc11-dfcf-4e98-9137-ce68403bb6ce
- Title
-
GeoNetwork UUID
- Language
- English
- Character encoding
- UTF8
- Contact
-
Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Point of contact Davies, G.
Type of resource
- Resource scope
- Document
- Name
-
GA publication: External publication
Alternative metadata reference
- Title
-
Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/124287
- Date info (Creation)
- 2018-05-04T03:37:56
- Date info (Revision)
- 2018-05-04T03:38:12
Metadata standard
- Title
-
AU/NZS ISO 19115-1:2014
Metadata standard
- Title
-
ISO 19115-1:2014
Metadata standard
- Title
-
ISO 19115-3
- Title
-
Geoscience Australia Community Metadata Profile of ISO 19115-1:2014
- Edition
-
Version 2.0, September 2018
- Citation identifier
- https://pid.geoscience.gov.au/dataset/ga/122551