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Last modified by robert on 2024/05/17 16:52
From version 6.2
edited by Sima Mousavi
on 2024/01/29 11:57
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To version 6.5
edited by Sima Mousavi
on 2024/01/29 14:36
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1 -=== **Silixa iDAS Setup Manual for Reoccupying/Duplicating Experiment** ===
1 += **What is iDAS?** =
2 2  
3 +**iDAS** stands for **Integrated Distributed Acoustic Sensing**. This advanced system utilizes the principle of Rayleigh backscattering in optical fibers to measure strain rates along the fiber's length. It's a cutting-edge technology predominantly used in fields like geophysics, where it's crucial for monitoring seismic activities, as well as in industrial applications like pipeline monitoring and security systems.
4 +
5 +=== **Safety first!**
6 + ===
7 +
8 +(% class="box warningmessage" %)
9 +The iDAS uses a Class 1 laser, which is generally considered safe for most applications. However, direct exposure to the eye should be avoided to prevent any risk of eye injury.
10 +\\Cables and fibers may create tripping hazards. Ensure that the routing of cables is done in a way that minimizes the risk of accidents.
11 +
3 3  ----
4 4  
5 -==== **General Information** ====
14 += **DAS Data Collection System** =
6 6  
16 +==== **1. Interrogator Unit** ====
17 +
18 +* **Function:** The interrogator unit is the core component of a DAS system. It sends laser pulses through the optical fiber and measures the backscattered light.
19 +* **Recording Information:** It records various settings such as the optical system configurations, spatial sampling rates, and the duration of data acquisition.
20 +* **Multiple Interrogators:** More than one interrogator may be used in an experiment. Each unit should have a unique identifier and is described in its respective metadata block.
21 +
22 +==== **2. Surface Installation** ====
23 +
24 +* **Cable Arrangement:** The optical fiber cable can be a single long continuous cable or multiple cables with connectors, used across different installation environments.
25 +* **Cable Types:** Cables may vary in construction types based on the installation environment.
26 +* **Geographical Metadata:** Parameters related to geographical location are specified for easy searchability in databases.
27 +
28 +==== **3. Fiber Optic Cable** ====
29 +
30 +* **Cable Composition:** Several optical fibers may be enclosed within one cable.
31 +* **Metadata Identification:** The metadata identifies each individual fiber used in the acquisition, including its intrinsic properties.
32 +
33 +==== **4. Installation Environments** ====
34 +
35 +* **Shallow Burial:** The cable can be shallowly buried.
36 +* **In-Conduit Installation:** The cable can also be installed within a conduit.
37 +* **Water Installation:** Suitable for underwater environments.
38 +
39 +==== **5. Channels** ====
40 +
41 +* **Sensor Distribution:** Channels represent sensors distributed along the fiber array at fixed intervals.
42 +* **Physical Location Determination:** The physical locations of these channels are ascertainable through methods like tap tests and GPS tracking.
43 +* **Metadata for Channels:** Each channel or group of channels has its own metadata block, detailing specifics like location and properties.
44 +
45 +
46 +[[image:1706489800616-982.png]]
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48 +
49 +
50 +[[image:1706488566274-805.png]]
51 +
52 +----
53 +
54 += **DAS Metadata Schema** =
55 +
56 +==== **1. Interrogator** ====
57 +
58 +* **Required:** Interrogator ID, manufacturer, model.
59 +* **Optional:** Serial number, firmware version.
60 +
61 +==== **2. Acquisition Parameters** ====
62 +
63 +* **Required:** Interrogator ID, acquisition ID, unit of measure, acquisition start and end time, acquisition sample rate, gauge length, number of channels, spatial sampling interval.
64 +* **Optional:** Pulse rate, pulse width.
65 +
66 +==== **3. Overview** ====
67 +
68 +* **Required:** Network code, location, start date, end date, point of contact.
69 +* **Optional:** Digital Object Identifier (DOI), purpose of data collection, funding agency.
70 +
71 +==== **4. Cable Information** ====
72 +
73 +* **Required:** Cable ID, cable bounding box.
74 +* **Optional:** Cable owner, cable installation date, cable characteristics.
75 +
76 +==== **5. Fiber Information ('Native format')** ====
77 +
78 +* **Required:** Cable ID, fiber ID, fiber geometry, fiber mode, fiber refraction index.
79 +* **Optional:** Fiber optical length, fiber start and end location, fiber one-way attenuation, fiber winding angle.
80 +
81 +==== **6. Channel Group** ====
82 +
83 +* **Required:** Interrogator ID, acquisition ID, channel group ID, cable ID, fiber ID, coordinate generation date.
84 +* **Optional:** Location method, coordinate reference frame, first/last usable channel ID, uncertainty of various coordinates (x, y, latitude, longitude, elevation, depth, strike, dip).
85 +
86 +==== **7. Channel** ====
87 +
88 +* **Required:** Channel group ID, channel ID, coordinates (x, y, latitude, longitude).
89 +* **Optional:** Elevation above sea level, depth below surface, distance along fiber, strike, dip.
90 +
91 +----
92 +
93 +=== ===
94 +
95 += **Pre-processing Steps for DAS Data (2.5 months, 90 TB)** =
96 +
97 +1. (((
98 +**Create a Deployment Log**
99 +
100 +* Document key details like photonics settings, duration of data collection, instances of hard disk failure, power outages, etc.
101 +)))
102 +1. (((
103 +**Generate Geographic Coordinates**
104 +
105 +* Assign latitude and longitude coordinates to each DAS channel for spatial referencing.
106 +)))
107 +1. (((
108 +**Data Conversion**
109 +
110 +* Convert the raw DAS time series data from counts to strain rate, which is more meaningful for seismic analysis.
111 +)))
112 +1. (((
113 +**Data Decimation**
114 +
115 +* Reduce the sampling rate from 1000 Hz to 100 Hz. This step is essential to manage data volume and focus on frequencies of interest for seismic activities.
116 +)))
117 +1. (((
118 +**Extract Specific Time Series**
119 +
120 +* Isolate time series data of special interest, such as those related to earthquake events, for detailed analysis.
121 +)))
122 +1. (((
123 +**Data Hosting**
124 +
125 +* Store the processed data on Research School of Earth Sciences (RSES) clusters and the National Computational Infrastructure (NCI) for accessibility and further analysis.
126 +)))
127 +1. (((
128 +**Extract Data and Instrument Response from Seismic Nodes**
129 +
130 +* Retrieve both the raw data and the corresponding instrument response characteristics for accurate interpretation of the seismic signals.
131 +)))
132 +1. (((
133 +**Long-term Archiving and Data Sharing**
134 +
135 +* Ensure that the data is archived in a format and location that supports long-term preservation and accessibility, such as the AuScope Distributed Acoustic Sensing (DAS) Collection.
136 +)))
137 +1. (((
138 +**Data Access and Record Keeping**
139 +
140 +* Maintain records and access paths (e.g., NCI local file path) for the data, including metadata and other associated records, to facilitate future research and data sharing.
141 +)))
142 +
143 +=== ===
144 +
145 +=== ===
146 +
147 +=== ===
148 +
149 +=== ===
150 +
151 +=== ===
152 +
153 +----
154 +
155 += **Silixa iDAS Setup Manual for Reoccupying/Duplicating Experiment** =
156 +
157 += **General Information** =
158 +
7 7  * **Experiment Name:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
8 8  * **Local Date:** ~_~_~_~_/~_~__**/202**
9 9  * **Local Time:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
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