A system for ocean bottom node (OBN) deployment can include a first deployment device located on a marine vessel, a second deployment device located on the marine vessel, a first line coupled to the first deployment device and comprising a first plurality of OBNs, and a second line coupled to the second deployment device and comprising a second plurality of OBNs. The first deployment device and the second deployment device can be configured to deploy and retract the first line and the second line simultaneously.

A method may be provided to operate a wireless terminal in communication with a network node. The method may include receiving a Physical Downlink Control Channel, PDCCH, order from the network node. The PDCCH order may include an identification for a Random Access CHannel RACH occasion to be used for a RACH message 1 preamble transmission. Moreover, the identification may include a first index that indicates a set of RACH occasions and a second index that indicates the RACH occasion associated with the set. The method may also include transmitting a Message 1 preamble to the network node using the RACH occasion responsive to the PDCCH order.

Provided are a device, method, and computer-readable recording medium for detecting an earthquake in a microelectromechanical system (MEMS)-based auxiliary seismic observation network. The method includes performing detrending of removing a moving average from original acceleration data received from single sensors of an MEMS-based auxiliary seismic observation network to preprocess the acceleration data, calculating a short-term average/long-term average (STA/LTA) value using a filter parameter value specified on the basis of the preprocessed acceleration data, generating an event occurrence message or event end message on the basis of the calculated STA/LTA value and transmitting the event occurrence message or event end message, when the event occurrence message is generated, calculating an earthquake probability through an earthquake detection deep learning model using the preprocessed acceleration data as an input, and analyzing noise by calculating a power spectral density (PSD) from the original acceleration data which is merged at certain intervals.

A correlated sparse nodes and mini-streamers system for collecting seismic data includes plural nodes distributed on the ocean bottom, and a mini-streamer spread that includes plural mini-streamers. The plural nodes and the mini-streamer spread are configured to simultaneously collect seismic data from a surveyed subsurface, and wherein a length of the mini-streamers is equal to or less than three times an inline distance between adjacent nodes of the plural nodes.

This disclosure presents processes and systems for generating an image of a subterranean formation from seismic data recorded in a seismic survey of the subterranean formation. The seismic data is contaminated with low frequency noise in a low frequency band. Processes and systems reconstruct seismic data in the low frequency band of the seismic data to obtain low frequency reconstructed seismic data that is free of the low frequency noise. The low frequency reconstructed seismic data is used to construct a velocity model of the subterranean formation. The velocity model and the low frequency reconstructed seismic data are used to generate an image of the subterranean formation that reveals structures of the subterranean formation without contamination from the low frequency noise.

An ocean bottom node for collecting seismic data, the ocean bottom node including a compounded housing including an electronics housing and a pinger housing, electronics located inside the electronics housing, and a battery pack configured to supply electrical power to the electronics. The pinger housing is permanently open to an ambient water while the electronics housing is sealed from the ambient water, and the pinger housing is configured to selectively and directly attach to the electronics housing.

The invention concerns a submarine exploration system (1) comprising: a master submarine drone (2) designed to move autonomously according to a predetermined flight plan (E) and comprising a communication module (C) for transmitting communication signals; a plurality of follower submarine drones (31, 32, 33, 34, 35, 36), each comprising at least one magnetic field detection system (D), each follower drone further comprising a communication module (C) for receiving communication signals from the master drone; the master drone being designed to transmit navigation instructions (I) to the follower drones and each follower drone being designed to move autonomously depending on the movement instruction such that its movement is slaved to the movement of the master drone.

Methods and apparatus are described for using ambient acoustic energy as a passive source in marine seismic surveys. An example embodiment includes (a) accessing signals that were recorded by sensors in the presence of acoustic energy that was emitted by a passive source during a marine seismic survey; (b) identifying a point to represent a location from which the acoustic energy was emitted; (c) isolating, from the recorded signals, a direct wavefield arriving at the sensors from a direction of the identified point; and (d) generating an estimated passive source wavefield at the identified point by backpropagating the isolated direct wavefield to the identified point. The estimated passive source wavefield may be used, together with signals recorded by the sensors, to generate an image of a subsurface earth volume without the use of active seismic sources.

A method may be provided to operate a wireless terminal in communication with a network node. The method may include receiving a Physical Downlink Control Channel, PDCCH, order from the network node. The PDCCH order may include an identification for a Random Access CHannel RACH occasion to be used for a RACH message 1 preamble transmission. Moreover, the identification may include a first index that indicates a set of RACH occasions and a second index that indicates the RACH occasion associated with the set. The method may also include transmitting a Message 1 preamble to the network node using the RACH occasion responsive to the PDCCH order.

A method for a marine seismic survey can include towing streamers that are spaced apart in a cross-line direction by a streamer separation (L) and towing seismic source elements that are spaced apart in the cross-line direction by a source separation based on an integer (k), an inverse of a quantity of the seismic source elements (1/S), and the streamer separation as represented by (k+1/S)L. The seismic source elements can be actuated and seismic signals can be detected at each of a plurality of receivers on the streamers.