活动变更或到期

当提醒发生变化时，发出引用之前提醒的新提醒。请勿更改或移除 Feed 中的现有提醒。等待适当的时间（例如 24-48 小时）后，从 Feed 中移除已取消、已更新或已过期的提醒。

请按以下方式处理事件更改或到期：

• UPDATE 或 CANCEL <msgType> 必须包含至少一个 <references> 元素。
• 您可以通过以下三种方式取消活动，优先级如下：
  1. 为每个事件设置 <expires> dateTime 值。在消息说明中，设置此提醒自行结束的预期时间。
  2. 稍后发出包含 <msgType> UPDATE、<responseType> "All Clear" 和 <expires> 的新 <alert> 消息。
  3. 使用 <msgType> CANCEL 发出新的 <alert> 消息。在 <references> 元素中，引用要取消的原始提醒。

示例

<alert xmlns="urn:oasis:names:tc:emergency:cap:1.2">
  <identifier>PAAQ-4-mg5a94</identifier>
  <sender>[e-mail]</sender>
  <sent>2013-01-05T10:58:23-00:00</sent>
  <status>Actual</status>
  <msgType>Update</msgType>
  <source>WCATWC</source>
  <scope>Public</scope>
  <code>IPAWSv1.0</code>
  <references>[e-mail],PAAQ-1-mg5a94,2013-01-05T09:01:16-00:00
   [e-mail],PAAQ-2-mg5a94,2013-01-05T09:30:16-00:00 [e-mail],
   PAAQ-3-mg5a94,2013-01-05T10:17:31-00:00</references>
  <incidents>mg5a94</incidents>
  <info>
    <category>Geo</category>
    <event>Tsunami Cancellation</event>
    <responseType>None</responseType>
    <urgency>Past</urgency>
    <severity>Unknown</severity>
    <certainty>Unlikely</certainty>
    <onset>2013-01-05T10:58:23-00:00</onset>
    <expires>2013-01-05T10:58:23-00:00</expires>
    <senderName>NWS West Coast/Alaska Tsunami Warning Center Palmer
     AK</senderName>
    <headline>The tsunami Warning is canceled for the coastal areas of
     British Columbia and Alaska from the north tip of Vancouver Island,
     British Columbia to Cape Fairweather, Alaska (80 miles SE of
     Yakutat).</headline>
    <description>The tsunami Warning is canceled for the coastal areas of
     British Columbia and Alaska from the north tip of Vancouver Island,
     British Columbia to Cape Fairweather, Alaska (80 miles SE of Yakutat).
     - Event details: Preliminary magnitude 7.5 (Mw) earthquake / Lat:
     55.300, Lon: -134.900 at 2013-01-05T08:58:20Z Tsunami cancellations
     indicate the end of the damaging tsunami threat. A cancellation is
     issued after an evaluation of sea level data confirms that a
     destructive tsunami will not impact the alerted region, or after
     tsunami levels have subsided to non-damaging levels.</description>
    <instruction>Recommended Actions: Don't re-occupy hazard zones until
     local emergency officials indicate it is safe to do so. This will be
     the last West Coast/Alaska Tsunami Warning Center message issued for
     this event. Refer to the internet site ntwc.arh.noaa.gov for more
     information. </instruction>
    <web>http://ntwc.arh.noaa.gov/events/PAAQ/2013/01/05/mg5a94/4/WEAK51/WEAK51.txt</web>
    <parameter>
      <valueName>EventLocationName</valueName>
      <value>95 miles NW of Dixon Entrance, Alaska</value>
    </parameter>
    <parameter>
      <valueName>EventPreliminaryMagnitude</valueName>
      <value>7.5</value>
    </parameter>
    <parameter>
      <valueName>EventPreliminaryMagnitudeType</valueName>
      <value>Mw</value>
    </parameter>
    <parameter>
      <valueName>EventOriginTime</valueName>
      <value>2013-01-05T08:58:20-00:00</value>
    </parameter>
    <parameter>
      <valueName>EventDepth</valueName>
      <value>5 kilometers</value>
    </parameter>
    <parameter>
      <valueName>EventLatLon</valueName>
      <value>55.300,-134.900 0.000</value>
    </parameter>
    <parameter>
      <valueName>VTEC</valueName>
      <value>/O.CAN.PAAQ.TS.W.0001.000000T0000Z-000000T0000Z/</value>
    </parameter>
    <parameter>
      <valueName>NWSUGC</valueName>
      <value>BCZ220-210-922-912-921-911-110-AKZ026&gt;029-023-024-019&gt;
      022-025-051258-</value>
    </parameter>
    <parameter>
      <valueName>ProductDefinition</valueName>
      <value>Tsunami cancellations indicate the end of the damaging tsunami
       threat. A cancellation is issued after an evaluation of sea level
       data confirms that a destructive tsunami won't impact the alerted
       region, or after tsunami levels have subsided to non-damaging
       levels.</value>
    </parameter>
    <parameter>
      <valueName>WEAK51</valueName>
      <value>Public Tsunami Warnings, Watches, and Advisories for AK, BC,
       and US West Coast</value>
    </parameter>
    <parameter>
      <valueName>EAS-ORG</valueName>
      <value>WXR</value>
    </parameter>
    <resource>
      <resourceDesc>Event Data as a JSON document</resourceDesc>
      <mimeType>application/json</mimeType>
      <uri>http://ntwc.arh.noaa.gov/events/PAAQ/2013/01/05/mg5a94/4/WEAK51/PAAQ.json</uri>
    </resource>
    <area>
      <areaDesc>95 miles NW of Dixon Entrance, Alaska</areaDesc>
      <circle>55.3,-134.9 0.0</circle>
    </area>
  </info>
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
  ...
</Signature>
</alert>