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Fig. 2 | Earth, Planets and Space

Fig. 2

From: Continuous seismic monitoring of Nishinoshima volcano, Izu-Ogasawara, by using long-term ocean bottom seismometers

Fig. 2

Seismic records for events collected by LT-OBSs deployed near Nishinoshima (left and upper right) and obtained epicenters for the events (lower right). Left: waveforms of typical characteristic events recorded by NI21. A waveform without filtering (uppermost) and with bandpass filtering of various frequency bands (lower) are shown. Traces indicate ground velocity, and scales are shown on the right corners of each trace. The small-amplitude high-frequency component arrives early, followed by large-amplitude waves with a period of a few seconds. Data with a frequency band of 4–8 Hz have the highest S/N ratio. Upper right: bandpass-filtered (4–8 Hz) records of the event recorded with LT-OBSs. The event occurred during the first-term observation and records from all LT-OBSs are shown. Red inverted triangles denote first arrivals. NI11 has the latest arrival among the stations. Lower right: red circles and blue squares show epicenters and positions of LT-OBSs, respectively. Epicenters of the events are concentrated in Nishinoshima

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