Offshore geodetic data conducive to the estimation of the afterslip distribution following the 2003 Tokachi-oki earthquake

Baba, Toshitaka; Hirata, Kenji; Hori, Takane; Sakaguchi, Hiroki

doi:10.1016/j.epsl.2005.10.019

Cited by 77 publications

(86 citation statements)

References 28 publications

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“…The correction by Baba et al (2006) is equivalent to the zero-lag correction. At high frequencies (>10 −2 hour −1 ), the correction using the estimated pairs of the regression coefficient and the lag yields a greater reduction in the amplitude than does the zero-lag correction.…”

Section: Usefulness Of the Obtm Data After Temperature Correctionsmentioning

confidence: 99%

“…In this paper, pressure gauges, derived from the HP measurement system, deployed on cabled observatories are referred to as ocean bottom tsunami meters (OBTMs) (e.g., Matsumoto et al, 2003;Tsushima et al, 2009). Baba et al (2006) detected a large vertical seafloor elevation of tens of centimeters, related to the 2003 Tokachi-oki earthquake (M w 8.0), from OBTMs off Kushiro operated by JAMSTEC (Hirata et al, 2002). The detection capability was clearly improved by correcting the OBTM records using a regression coefficient to the temperature changes.…”

Section: Introductionmentioning

confidence: 99%

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Temperature correction and usefulness of ocean bottom pressure data from cabled seafloor observatories around Japan for analyses of tsunamis, ocean tides, and low-frequency geophysical phenomena

Inazu

Hino

2011

Earth Planet Sp

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Ocean bottom pressure (OBP) data obtained by cabled seafloor observatories deployed around Japan, are known to be significantly affected by temperature changes. This paper examines the relationship between the OBP and temperature records of six OBP gauges in terms of a regression coefficient and lag at a wide range of frequencies. No significant temperature dependency is recognized in secular variations, while substantial increases, at rates of the order of 1 hPa/year, are commonly evident in the OBP records. Strong temperature dependencies are apparent for periods of hours to days, and we correct the OBP data based on the estimated OBP-temperature relationship. At periods longer than days, the temperature corrections work well for extracting geophysical signals for OBP data at a station off Hokkaido (KPG2), while other corrected data show insufficient signal-to-noise ratios. At a tsunami frequency, the correction can reduce OBP fluctuations, due to rapid temperature changes, by as much as millimeters, and is especially effective for data at a station off Shikoku (MPG2) at which rapid temperature changes most frequently occur. A tidal analysis shows that OBP data at a station off Honshu (TM1), and at KPG2, are useful for studies on the long-term variations of tidal constituents.

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Section: Usefulness Of the Obtm Data After Temperature Correctionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temperature correction and usefulness of ocean bottom pressure data from cabled seafloor observatories around Japan for analyses of tsunamis, ocean tides, and low-frequency geophysical phenomena

Inazu

Hino

2011

Earth Planet Sp

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“…The difference between two measurements includes coseismic deformation as well as postseismic and interseismic deformations. After the establishment of a nationwide GPS network (GEONET) in 1994, interseismic, coseismic, and postseismic deformations were continuously observed in Hokkaido (e.g., Sagiya et al, 2000;Ozawa et al, 2004;Baba et al, 2006;Suwa et al, 2006). We can use the average GPS velocity in the period when no large events occur for the adjustment of the interseismic deformation.…”

Section: Introductionmentioning

confidence: 99%

Slip distribution of the 1973 Nemuro-oki earthquake estimated from the re-examined geodetic data

Nishimura

2009

Earth Planet Sp

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Geodetic data, including leveling, tide-gauge, triangulation/trilateration, and repeated EDM data, from eastern Hokkaido, Japan, were re-examined to clarify the crustal deformation associated with the 1973 Nemuro-oki earthquake. We inverted the geodetic data to estimate the slip distribution on the interface of the subducting Pacific plate. The estimated coseismic slip, potentially including afterslip, showed a patch of large slip (i.e., an asperity) near the epicenter of the mainshock. The moment magnitude of the Nemuro-oki earthquake was estimated to be 8.0 from the geodetic data, which is comparable to the 2003 M w = 8.0 Tokachi-oki earthquake. The estimated slip distribution suggests a 50 km-long gap in the coseismic slip between the 1973 Nemuro-oki and the 2003 Tokachi-oki earthquakes. The slip area of the 2004 M w = 7.0 Kushiro-oki earthquake, estimated from GPS data, was located at the northwestern edge of the Nemuro-oki earthquake, which implies that the area may have acted as a barrier during the Nemuro-oki earthquake. The postseismic deformation observed by leveling and tide-gauge measurements suggests that the afterslip of the Nemuro-oki earthquake occurred at least in a western and northern (i.e., deeper) extension of the asperity on the plate interface.

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“…[17] The fitness between the observed and predicted pressure residuals is better in PG2 than PG1 (Figures 3a and 3b) because the correlation between temperature and pressure residual is practically better in PG2 [Baba et al, 2006]. The effective time scale of the transient thermal responses is, however, approximately 180 and 60 minutes for PG1 and PG2, respectively.…”

Section: Discussionmentioning

confidence: 99%

Transient thermal response in ocean bottom pressure measurement

Hirata

Baba

2006

Geophysical Research Letters

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Offshore ocean bottom pressures usually follow ocean tidal motion but sometimes deviate from it even when no tsunami occurs. Numerous observations suggest that such deviations highly correlate with sudden temperature changes, probably due to irregular deep ocean currents, around the pressure gauges regardless of static temperature compensation mechanism. We ascribe this deviation to the transient thermal response of the pressure gauges, which produce apparent pressure fluctuations when temperature change quickly so that temperature equilibrium condition of two quartz transducers is not valid. We put forward an empirical method to estimate the transient thermal response correctly. Such rapid temperature change may have to be corrected for a robust tsunami warning based on offshore tsunami observation with pressure gauges.

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Offshore geodetic data conducive to the estimation of the afterslip distribution following the 2003 Tokachi-oki earthquake

Cited by 77 publications

References 28 publications

Temperature correction and usefulness of ocean bottom pressure data from cabled seafloor observatories around Japan for analyses of tsunamis, ocean tides, and low-frequency geophysical phenomena

Temperature correction and usefulness of ocean bottom pressure data from cabled seafloor observatories around Japan for analyses of tsunamis, ocean tides, and low-frequency geophysical phenomena

Slip distribution of the 1973 Nemuro-oki earthquake estimated from the re-examined geodetic data

Transient thermal response in ocean bottom pressure measurement

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