Reflection seismic study of the Siljan Ring impact structure: Mora - Time-depth migrated data

Two new reflection seismic profiles over the Paleozoic successions of the western part of the Siljan Ring impact structure were acquired during 2011, the Mora and the Orsa profile. This data set concerns the Mora profile. The profile has length of c. 10 km and the processed data image the geological section to about 3 km depth. During the survey, 391 source points (VIBSIST 3000) were recorded by 320 receiver channels for 30 seconds. From this recording, the following data sets were generated and are published here: 1) decoded and quality controlled raw data; 2) pre-processed (shot geometry applied) data; 3) stacked data; 4) migrated data; 5) depth converted data and velocity field. Key acquisition parameters are: Number of channels: 320 (160-160) Near offset: 0m Geophone spacing: 10 m Geophone type: 28 Hz single Source spacing: 20 m Source type: VIBSIST 3000 Hit interval between hammer blows: 100-200 ms Sweeps per source point: 3-4 Nominal fold: 80 Recording instrument: SERCEL 428UL Sample rate: 1 ms Field low cut: Out Field high cut: 400 Hz Record length: 30 s Profile length: 10 km Source points: 391 Dates acquired: 3/6-9/6: 2011 This dataset contains processed data of the Mora profile: Processing steps for this data set: 1: Read decoded VIBSIST data 2: Bulk static shift to zero time 3: Apply geometry 4: Pick first breaks 5: Spherical divergence correction 6: Trace editing 7: Trace balance: 0–3000 ms 8: Spectral equalization: 0–600 ms: 50–80–200–240 Hz; 700–1500 ms: 40–70–180–240 Hz 9: Time variant bandpass filter: 0–400 ms: 50–80–240–360 Hz; 450–600 ms: 45–70–210–300 Hz; 700–1000 ms: 40–60–180–270 Hz; 1100–3000 ms: 35–50–150–225 Hz 10: Refraction statics: datum 160 m, replacement velocity 3000 m/s 11: Residual statics 12: Median filter: 11 traces, 3 samples, 5300 m/s, subtract 13: AGC: 50 ms 14: Mute: top and bottom 15: Residual statics 16: Velocity analysis 17: NMO correction: 70% stretch mute 18: Trace balance 19: FX Decon: 19 trace window 20: No dip filter 21: Trace balance 22: Stolt migration: 200–3000, 1000–4000 ms/s 23: Time-depth conversion Processed seismic data stored as one file for the enitre seismic profile, according to SEG technical standard SEG-Y revision 1 (SEG-Y_r1.0, 2002); https://seg.org/Publications/SEG-Technical-Standards

2011年，针对锡利扬环形撞击构造（Siljan Ring impact structure）西部的古生代地层序列，采集了两条全新的反射地震剖面，分别命名为莫拉（Mora）剖面与奥尔萨（Orsa）剖面。本数据集对应莫拉剖面。该剖面总长约10 km，经处理后的地震数据可成像约3 km深度范围内的地质剖面。
本次勘探采用VIBSIST 3000型震源，共布设391个震源点，由320道接收通道记录时长30秒的地震信号。基于本次采集的原始记录，共生成并公开发布以下5类数据集：1）经解码与质量控制的原始地震数据；2）经预处理（已应用炮点几何参数）的数据；3）叠加数据；4）偏移成像数据；5）深度转换数据与速度场。
核心采集参数如下：
接收道数：320（160-160）
近偏移距：0 m
检波器间距：10 m
检波器类型：28 Hz单分量检波器
震源间距：20 m
震源类型：VIBSIST 3000
锤击间隔：100–200 ms
单震源点扫描次数：3–4次
理论覆盖次数：80
记录仪器：SERCEL 428UL
采样率：1 ms
野外低截止滤波：无
野外高截止滤波：400 Hz
记录时长：30 s
剖面长度：10 km
震源点数量：391
采集日期：2011年6月3日至6月9日
本数据集包含莫拉剖面的处理后地震数据，具体处理流程如下：
1. 读取解码后的VIBSIST原始数据
2. 执行整体静校正至零时刻
3. 应用炮点几何参数
4. 拾取初至波
5. 球面发散校正
6. 道编辑
7. 道平衡处理（处理时窗：0–3000 ms）
8. 频谱均衡：0–600 ms频段采用50–80–200–240 Hz滤波参数；700–1500 ms频段采用40–70–180–240 Hz滤波参数
9. 时变带通滤波：0–400 ms频段：50–80–240–360 Hz；450–600 ms频段：45–70–210–300 Hz；700–1000 ms频段：40–60–180–270 Hz；1100–3000 ms频段：35–50–150–225 Hz
10. 折射静校正：基准面高程160 m，替换速度3000 m/s
11. 剩余静校正
12. 中值滤波：采用11道、3采样点窗口，速度参数5300 m/s并做减法处理
13. 自动增益控制（AGC）：时窗长度50 ms
14. 信号切除：顶部与底部切除
15. 剩余静校正
16. 速度分析
17. 正常时差（NMO）校正：设置70%拉伸切除阈值
18. 道平衡处理
19. FX反褶积：采用19道滑动窗口
20. 无倾角滤波
21. 道平衡处理
22. Stolt偏移成像：速度范围设置为200–3000、1000–4000 m/s
23. 时深转换
处理后的地震数据以单个文件存储完整地震剖面，符合SEG技术标准SEG-Y修订版1（SEG-Y_r1.0, 2002）；相关标准详情可参考：https://seg.org/Publications/SEG-Technical-Standards