Changing Priorities
Rarely a month goes by without the sad news of another natural disaster. Unfortunately, this is a trend that is increasing as earth changes.
On a positive note, we have the ability to reduce the human cost of natural disasters such as earthquakes. Offshore technology can efficiently and cheaply help us monitor, adapt to and mitigate natural disasters such as earthquakes. Offshore submarine cables also have the potential to be impactful in stimulating collaboration across national boundaries. Lack of data and the need for early warning are critical hurdles that need to be prioritised for any benefit to be realised.
To warn better, we need to monitor better.
Changing Earth
The Anthropocene period in earth’s history points to humanity’s direct impact on earth’s condition, properties and processes.[1] Research observing earth’s landscape, biodiversity, global atmospheric temperatures, sea level height, etc., confirms the physical representation of the Anthropocene in our towns, cities, rivers and oceans.[2] In summary, human activity is changing earth and the global environment, ushering in a new geological epoch.
Human-made changes to earth affect the nature and reach of natural disasters. For instance, chemical and biological changes to earth’s atmosphere such as increasing greenhouse gases alters the heat and gas distribution of the planet. This affects precipitation, ocean circulation, temperatures, the state of the polar regions, storm patterns and sea level rise.[3] The nature and scale of earthquake devastation is part of earth’s story and with oceans defining the physical features of earth,[4] we need to look offshore for adaptation and mitigation possibilities.
Comprising approximately 70% of the earth, oceans define earth and should be prioritised in efforts to understand earth, its processes and stressors.
Changing Reach
The earth is in constant motion. Slabs of the earth’s crust or tectonic plates move away and towards each other. An earthquake happens when the plates can no longer resist the stress and slip.
Data about earthquakes are subject to the diversity of the earth’s crust so different tectonic environments will generate case-specific data. The reality is that information on stress distribution of the earth’s crust is varied at best with some areas lacking relevant data. To further complicate things, it is difficult to predict the final magnitude of an earthquake using waveform data at the onset of quaking.[5] Put simply, and paraphrasing Charles Richter, it is an impossible endeavour to attempt to predict an earthquake. We need a renewed focus on the global ocean because ocean monitoring is key to making earthquake prediction possible.
Efforts to mitigate and adapt to the effects of earthquakes should also be borderless.
Ocean Monitoring for Better Data
Whilst we know that there are seismically active areas on earth’s mantle, our knowledge of these processes is inadequate. Infrastructure for detection and characterisation of earthquakes is needed in the global ocean. Recent reports of the Turkey-Syrian earthquake use data from space infrastructure[6] whereas the Anatolian plate straddles the Mediterranean sea southwards, the Aegean sea westwards, and the Black sea northwards.[7] Better fault identification is vital to monitoring and interpreting seismic data but insufficient data persists[8]because offshore monitoring is not robust. Ongoing monitoring of seismic activity is also valuable for data on patterns of stress distribution and aftershocks.
Physical, chemical and biological interactions in the global ocean are poorly understood yet highly impactful to humanity.
Ocean Monitoring for Early Warning
As modifiers of earth’s nature and processes, we need to improve existing deficiencies in our understanding of earth. Earthquake early warning systems predominantly rely on onshore networks but the first steps to damaging events occur in offshore subduction zones.[9]This is compounded by the fact that earthquake early warnings have shorter lead times compared to other natural disasters.[10] There is a need for better sensing for longer lead times.
Disasters such the recent Turkey-Syria earthquake show weak points in ocean monitoring and reinforces the need to lengthen lead times. Submarine fibre-optic cables can be used to provide data on earth’s processes, improve climate monitoring systems and also better early warning protocols that is timely and targeted.[11]Offshore observation has had some early adopters[12] but prioritising a global system of observation is the first step towards better mitigation and adaptation in the Anthropocene.
[1] Zalasiewicz J, Williams M, Steffen W & Crutzen P, The New World of the Anthropocene. Environmental Science & Technology, 44, 2228-2231. https://doi.org/10.1021/es903118j.
[2] Zalasiewicz J, Williams M, Smith A, Barry TL, Coe AL, Bown PR, Brenchley P, Cantrill D, Gale A, Gibbard P, Gregory FJ. Are We Now Living in the Anthropocene? GSA Today. 2008 Feb 18;18(2):4. https://www.geosociety.org/gsatoday/archive/18/2/pdf/i1052-5173-18-2-4.pdf
[3] Verlaan P, Rogers A and Preston G, Anthropogenic Threats to Seamount Ecosystems and Biodiversity (IUCN, 2012). 28. https://portals.iucn.org/library/node/10301.
[4] Global Ocean Science Report 2020: Charting Capacity for Ocean Sustainability https://en.unesco.org/gosr
[5] Kamigaichi O. (2004). “JMA Earthquake Early Warning”. Journal of Japan Association for Earthquake Engineering, 4: 3 (Special Issue), 134-137. https://doi.org/10.5610/jaee.4.3_134
[6] See https://www.emsc-csem.org/Earthquake/271/Earthquake-sequence-in-Turkey-February-6th-2023. Plates were captured by Global Navigation Satellite System with geodetic data from GPS observations days before the 6 February 2023 event. Whilst there were tide gauge observations of waves, there was no data from offshore bottom sensors. See also https://www.bbc.co.uk/news/science-environment-64603521
[7] https://www.geolsoc.org.uk/Policy-and-Media/Outreach/Plate-Tectonic-Stories/Great-Glen-Fault/North-Anatolian-Fault
[8] Wang S and others, 'Structural Augmentation in Seismic Data for Fault Prediction' (2022) 12 Applied Sciences 9796. https://doi.org/10.3390/app12199796
[9] Allen RM and Melgar D, Earthquake Early Warning: Advances, Scientific Challenges, and Societal Needs (2019) 47 Annual Review of Earth and Planetary Sciences 361-388. 379 https://doi.org/10.1146/annurev-earth-053018-060457
[10] Wald DJ, 'Practical Limitations of Earthquake Early Warning' (2020) 36 Earthquake Spectra 1412. 1413. https://doi.org/10.1177/8755293020911388.
See also, Minson SE and others, 'The Limits of Earthquake Early Warning Accuracy and Best Alerting Strategy' (2019) 9 Scientific Reports 2478. https://doi.org/10.1038/s41598-019-39384-y
[11] Howe BM and others, 'SMART Cables for Observing the Global Ocean: Science and Implementation' (2019) 6 Frontiers in Marine Science. https://www.frontiersin.org/articles/10.3389/fmars.2019.00424/full
[12] Aoi S and others, 'MOWLAS: NIED Observation Network for Earthquake, Tsunami and Volcano' (2020) 72 Earth, Planets and Space 126. 11 https://doi.org/10.1186/s40623-020-01250-x. S-net is a network of approx. 150 nodes on more than 800km of submarine fibre-optic cables covering the Japan trench. It is exemplary in showing the potential to speed up disaster detections and warnings as we push for real-time ocean bottom networks.