Multi-phase seismic source imprint of tropical cyclones

Abstract

The coupling between the ocean activity driven by winds and the solid Earth generates seismic signals recorded by seismometers worldwide. The 2–10 s period band, known as secondary microseism, represents the largest background seismic wavefield. While moving over the ocean, tropical cyclones generate particularly strong and localized sources of secondary microseisms that are detected remotely by seismic arrays. We assess and compare the seismic sources of P, SV, and SH waves associated with typhoon Ioke (2006) during its extra-tropical transition. To understand their generation mechanisms, we compare the observed multi-phase sources with theoretical sources computed with a numerical ocean wave model, and we assess the influence of the ocean resonance (or ocean site effect) and coastal reflection of ocean waves. We show how the location and lateral extent of the associated seismic source is period- and phase-dependent. This information is crucial for the use of body waves for ambient noise imaging and gives insights about the sea state, complementary to satellite data.

Seismic Signature of the Super Cyclone Amphan in Bay of Bengal Using Coastal Observatories Operating Under National Seismological Network of India

“…Gualtieri et al (2018) suggested an adaptative statistical model, which demonstrated the relationship between the spectral amplitude of the short-period secondary microseism and the tropical cyclone intensity in the northwest Pacific Ocean. In addition to background noise, the body waves or multi-phase seismic sources were also found to be associated with cyclones, and it was successfully demonstrated by a few researchers (Gualtieri et al, 2018;Retailleau & Gualtieri, 2021). It is now believed that the seismological tools could be better used to track the path of the cyclone juxtaposed oceanic wave models with several limitations, including a resolution that is found to be too coarse for tropical cyclones producing aliasing, underdetermining the wind speeds and oceanic wave heights, and computing facilities etc (Chi et al, 2010;Fan et al, 2019;Retailleau & Gualtieri, 2019;Sufri et al, 2014;Zhang et al, 2010).…”

“…The energy bands from 0.05 to 0.10 Hz are clearly recognized in the spectrograms. PSD analysis as single-frequency microseism bands, or primary energy from Oceanic waves (Hasselmann, 1963), and 0.10-0.50 Hz energy spectrum is considered secondary microseisms (Cessaro, 1994;Longuet-Higgins, 1950;Retailleau & Gualtieri, 2021). Bromirski et al (2005) further classified double-frequency microseism as short-period (0.20-0.45 Hz) double-frequency and long-period (0.085-0.2 Hz) double-frequency energy bands.…”

“…The accepted mechanisms responsible for the generation of SBNs are (a) direct coupling between oceanic waves in shallower water and that near the seafloor in the 10–20 s period (Webb, 2002) and (b) nonlinear interaction of two sets of opposite moving oceanic gravity waves having similar frequency content that generate <10 s microseism (Ekström & Ekström, 2005; Longuet‐Higgins, 1950; Rhie & Romanowicz, 2004). A tropical cyclone is found to be one of the most powerful storms capable of producing generally seismic noise of secondary microseisms type, whose sources are much localized (Gualtieri et al., 2018; Retailleau & Gualteri, 2021; Singh et al., 2020).…”

“…It may be noted that the last super cyclone that hit the Odisha coastal region occurred in the Bay of Bengal about two decades ago, in 1999, which killed more than 10,000 people and caused huge economic devastation in the area (Thomalla & Schmuck, 2004). A large‐scale dynamic of the oceanic phenomena usually drives the energy into the earth in the form of seismic waves and modifies the seismic background vibrations significantly in the near coast regions (e.g., Adimah & Padhy, 2020; Chi et al., 2010; Gaebler & Ceranna, 2021; Gerstoft et al., 2006; Gualtieri et al, 2018; Pandey et al, 2020; Retailleau & Gualtieri, 2021).…”

Beamforming of Rayleigh and Love Waves in the Course of Atlantic Cyclones

“…Ocean microseisms are generally divided into primary (PM), having the same frequency as the causative SGW and being generated often close to the shore, and secondary microseisms (SM), with twice the frequency of the forcing SGW. Teleseismic observations of both, deep‐ and shallow‐water microseisms exist (e.g., Beucler et al., 2015; Kedar et al., 2008; Landès et al., 2010; Traer et al., 2012; Ying et al., 2014) and the theoretical understanding of the ocean‐seafloor‐subsurface coupling has been developed since early works (e.g., Longuet‐Higgins, 1950, 1953) up to more recent advances (e.g., Ardhuin et al., 2011; Retailleau & Gualtieri, 2021). However, a detailed knowledge on the localization of the cyclone‐related microseismic sources, as well as their shape, spectral characteristics and their exact relation with the physical properties of the generating cyclones is still in development.…”