IS428 AY2019-20T1 Assign Nurul Khairina Binte Abdul Kadir TaskFindings Q2
VAST 2019 MC1: Crowdsourcing for Situational Awareness
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Question: Use visual analytics to show uncertainty in the data. Compare the reliability of neighborhood reports. Which neighborhoods are providing reliable reports? Provide a rationale for your response. Limit your response to 1000 words and 10 images.
Contents
Insights
In order to assess the reliability of the reports, we will consider the following factors:
• A surge of reports were made before the earthquake
• Delay in reports due to power outage and reports made after the earthquake
• Comparison of maximum impact scores over time (Pre, Major and Post earthquake)
• Variation in reported impact levels by neighbourhoods in the same region. The region is based on the estimated distance to the epicentre of the earthquake (Close, Moderate, Far and Very Far). The variation within the neighbourhood can also be observed.
• Relationship between shake intensity and other damage types to analyze damage uncertainty
This is the timeframe that we will be using for this analysis.
A. Pre-Earthquake – 6 April to 8 April
B. Major Earthquake – 8 April. Note this refers to the day of the earthquake
C. Post-Earthquake – 9 April to 11 April
| Summary | Detailed Description |
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We will analyze the data for the Pre-Earthquake Period (before 8 April). The filter is used to focus on this data. There is a spike in the number of reports on 6 April, 4 PM. We can see that Old Town, Scenic Vista and Broadview made a high number of reports at this timing across all damage types. Note that impact scores that are Null are not filtered out in this analysis.  With reference to the shake map on 6 April, the shaking intensity was ‘Not Felt’. We will focus on this timing 6 April, 4 PM to 6 PM for this analysis. Since the shaking is Not Felt, we should expect less damage during this time period. We can expect some reports coming from the 3 neighbourhoods closest to the epicenter which is Old Town, Safe Town, and Cheddar Ford but the impact level shouldn’t be high.  The average shake intensity for Safe Town was 2. The damage type filter for the mode chart is set to Shake Intensity. Safe Town was the only town with a mode of Weak from 4 PM to 6PM. At 7 PM, the mode changed back to Not Felt Since it is close to the source of the earthquake, it is acceptable and not an anomaly. The citizens might have overestimated the intensity of the shaking.  Another possibility of why there is a surge of reports could be due to maintenance work. For example, we will focus on Roads and Bridges damages. There is maintenance work going on at Cheddarford which will result in delays. There is also more than 1 mode in the chart for Cheddarford and this is on 6 April, 6 PM which is 2 hours after the spike in reports.  | |
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We can observe a surge in reports for Old Town, Scenic Vista, Broadview and Chapparal on 9 April. All of them show a similar pattern of a gap of not having any reports made before the surge. Chapparal had 1375 reports and Old Town had 4490 reports once power was restored. However, only a small number of reports were made by Wilson Forest once power was restored and it was only for 4 hours since there was another gap after 7 PM on 9 April.  In order to confirm that a power outage is the reason behind the surge of reports, we can analyze the Mode of Power Damages By Neighbourhood chart. For instance, on 8 April at 8 AM, the mode of impact score for Power was ‘Violent’ for Chapparal. 1 hour later, there were no reports made by Chapparal. Since it was so violent, the power could have been cut off. In fact, there were no reports made till 9 April at 4 AM and we can infer that the power was restored at that time.  The power outage can affect the accuracy of the true extent of the damage and affect the emergency response plan. Once the power is restored, the backlog starts to flow which results in a spike in the number of reports that were originally made on 8 April and not 9 April. Lastly, reports were still being made after the earthquake. There is a spike in reports on 9 April, 3 PM.  There is a possibility that there was another small earthquake that happened after the main one on 8 April. The source of the 2nd earthquake could have been in the same area since the same neighborhoods reported a higher average impact score as compared to the rest. Since more than 3 neighbourhoods reported shaking after the earthquake, it should be regarded seriously.  | |
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We are assuming that there is no 2nd earthquake on 9 April in this analysis. Hypothesis: The maximum impact score before the earthquake (pre-earthquake) and after the earthquake (post-earthquake) should NOT be higher than the maximum impact score on the day of the earthquake (major earthquake). These are the results when we compare between Major Earthquake and Post Earthquake: For Medical damages, Cheddarford has a maximum impact score of 7 for Major Earthquake (1 report) and 9 for Post Earthquake (2 reports).  For Shake Intensity, Chapparal has a maximum impact score of 4 for Major Earthquake (1 report) and 5 for Post Earthquake (1 report). This report is inaccurate and 1 person could have reported it wrongly.  Through this analysis, we can also conclude that using the maximum as a metric is not advisable since outliers will be considered as the maximum even if they are inaccurate. | |
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This is the time frame used for the following analysis: 8 April 8 AM to 9 AM. The reliability check preset is set to compare the impact scores 0 to 3 (in green) and 8 to 10 (in red) which are the 2 extreme ends. On 8 April from 8 AM to 9 AM, we can see that Old Town made the largest number of reports with impact score (8 to 10). This is extremely large as compared to other neighbourhoods that are close to the epicenter. Safe Town also made a larger proportion of reports with impact scores from 0 to 3 as compared to 8 to 10.  | |
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idk what to write for this yet
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