Normandino Carreras

Ocean Bottom Seismometer: Design and Test of a Measurement System for Marine Seismology

The Ocean Bottom Seismometer (OBS) is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents a new Ocean Bottom Seismometer designed to be used in long duration seismic surveys. Power consumption and noise level of the acquisition system are the key points to optimize the autonomy and the data quality. To achieve our goals, a new low power data logger with high resolution and Signal–to-Noise Ratio (SNR) based on Compact Flash memory card is designed to enable continuous data acquisition. The equipment represents the achievement of joint work from different scientific and technological disciplines as electronics, mechanics, acoustics, communications, information technology, marine geophysics, etc. This easy to handle and sophisticated equipment allows the recording of useful controlled source and passive seismic data, as well as other time varying data, with multiple applications in marine environment research. We have been working on a series of prototypes for ten years to improve many of the aspects that make the equipment easy to handle and useful to work in deep-water areas. Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years. OBS sensors recording motion of the ocean floor hold key information in order to study offshore seismicity and to explore the Earth’s crust. In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface. The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure.

Digital system for monitoring volcanic seismicity

To control and preventing volcanic risk, are used different devices where many parameters are monitored that provide insight into the state of a volcano. This paper presents the design of system for monitoring the volcano seismicity. This system is composed of the module of acquisition data, the power module, the peripherals for communicate remotely and GPS to get time synchronization. This system is proposed to have a quick deployment in case of volcanic crisis, with a low cost of construction and maintenance. At the same time the equipment is built inside a watertight box, which allows installation of the system in adverse conditions and in remote locations with difficult access. The graph that can be seen in the results section shows a correct system operation.

Multi-platform underwater passive acoustics instrument for a more cost-efficient assessment of ocean ecosystems

This paper describes the development of cost-efficient, innovative and interoperable ocean passive acoustics sensors systems deployable from multiple platforms in the European FP7 project NeXOS (Next generation Low-Cost Multifunctional Web Enabled Ocean Sensor Systems Empowering Marine, Maritime and Fisheries Management). The objective of the NeXOS project is to develop cost-effective, innovative, and compact multifunctional sensor systems in ocean optics, ocean passive acoustics and for an Ecosystem Approach to Fisheries (EAF), which can be deployed from mobile and fixed platforms, with data services contributing to the GEOSS, the Marine Strategy Framework Directive (MSFD) and the Common Fisheries Policy of the European Union. Development of a new generation of multifunctional sensor systems is underway to address ocean monitoring challenges. The development of innovative hydrophones will focus on the pre and post-processing of acoustic information and improved transducer integration, reducing size and overall procurement and operations cost while increasing functionality. An important part of the effort will focus on the need for greater dynamic range and the integration on autonomous platforms, such as gliders and profilers.

The unit control of an acquisition system for Ocean Bottom Seismometer (OBS)

In this paper we talk about an acquisition system for seismic data. The Ocean Bottom Seismometer (OBS) is equipment designed to obtain the seismic marine data from the seabed. The main part of this paper is based in an application which controls the acquisition data of four measurement channels. This system has been tested in lab, getting the corresponding results.