K-CHIRP MODEL 3310 SUB BOTTOM PROFILE

Sub-bottom profiling systems are used to identify and characterize layers of sediment or rock under the seafloor. The technique used is similar to a simple echosounder. A transducer emits a sound pulse vertically downwards towards the seafloor, and a receiver records the return of the pulse once it has been reflected off the seafloor. Parts of the sound pulse will penetrate the seafloor and be reflected off of the different sub-bottom layers. The data that is obtained using this system provides information on these sub-floor sediment layers.

Sub-bottom profiling systems utilize the principle of seismic reflection. Seismic reflection uses a stronger sound signal than echolocation and lower sound frequencies. The sound pulse is often sent from an airgun towed behind the ship. An airgun uses the sudden release of compressed air to form bubbles. The bubble formation produces a loud sound. The sound from the airgun travels down to the seafloor. Some of the sound reflects off the seafloor but some of the sound penetrates the seafloor. The sound that penetrates the seafloor may also reflect off layers of material within the seafloor. The reflected sounds travel back up to the surface. The ship also tows a number of hydrophones (called a towed array or streamer) which detects the reflected sound signal when it reaches the surface. The time it takes the sound to return to the ship can be used to find the thickness of the layers in the seafloor and their position (sloped, level, etc). It also gives some information about the composition of the layers

Sub bottom profilers work on the same principle as simple echosounders, but use much lower frequency acoustic energy. The acoustic pulses penetrate below the seabed and into the sediment. Returning echoes from sub bottom features such as geological stratas or buried material create a trace on paper and in the digital record.

Overall characteristics of K-CHIRP 3310

 

Host Sonar	3000 Side Scan Sonar
Frequency (Chirp)	2-8 kHz
Beam	@ 5kHz 20° along track and 40° crosstrack
Selectable pulses (sync to side scan rate)	to 30 PPS
Selectable Pulse lengths	2.5,5,10,20,30 msec (limited by side scan range scale)
Resolution	to 12.5 cm
Power	1 KW (peak)
Source Level	204 dB re 1μPa @ 1m
Depth Rating	600 meters
Weight in Air	123 kg, 270 pounds incl. side scan
Software	SonarPro®
Tow Cable	Single 50 ohm Coax
Data format	SDF , XTF, SEG-Y
Sea Bed Penetration	5-50 Meters, Variable Depending upon Soil Density
Digitization	24 bit A/D

 

Application:

• Cable & Route Surveys
• Geophysical and Geological Surveys
• EEZ Surveys
• Sediment Classification
• Buried objects, Cables and Pipelines
• Dredging Surveys
• Hazards Surveys

Gli impulsi riflessi sono ricevuti dallo stesso trasduttore acustico usato per la trasmissione ed il segnale elettrico risultante è registrato su carta da un registratore grafico.
Il sistema si avvale della tecnologia digitale “Chirp” avanzata per produrre immagini ad alta risoluzione.
Nell’area da indagare, vengono effettuati dei transetti distanti tra loro a secondo del grado di risoluzione e di precisione che si vuole ottenere dal rilievo.

Il sistema S.B.P. è sempre costituito da una unità hardware che rimane a bordo della imbarcazione che registra e processa le informazioni acquisite e da un trasduttore racchiuso in un involucro pesciforme che viene immerso in mare fissato alla barca o portato a traino.